Ukrainian president Petro Poroshenko has introduced martial law to parts of his country as tensions with Russia escalate.

The Ukrainian parliament voted 272-30 in favour of a presidential edict calling for the measure’s introduction in the aftermath of a naval clash off the Crimean Peninsula on Sunday 25 November, which saw the Russian coastguard capture three Ukrainian ships and their 23 crew members on the Sea of Azov.

Russia accused the two Ukrainian artillery boats and a tug of crossing into its waters along the Kerch Strait without permission, despite the two nations having signed a 2003 maritime treaty agreeing the passage to the Black Sea was shared territory.

Moscow’s attitude to the region appears to have changed since then, however, its navy behaving increasingly aggressively since the illegal annexation of Crimea in 2014, with Ukrainians fearing the Vladimir Putin administration is seeking to control access to its ports in order to weaken the smaller nation’s economy.

But what exactly is martial law and what does it mean for the Eastern European nation?

Martial law is defined as the temporary imposition of military rule over a state or region in times of national crisis when civil authority has broken down or when wartime operations are underway.

The ordinary rule of law is postponed and the administration of government functions is overseen by the armed forces, ostensibly in the best interests of the public.

Ukrainian President Petro Poroshenko addresses lawmakers during an emergency session of Ukrainian Parliament in Kiev on 26 November 2018 (Vladimir Shtanko/Anadolu Agency/Getty)

But the principle has also been deployed by authoritarian regimes around the world as a means of suppressing popular dissent. China declared martial law to curtail the Tiananmen Square demonstrations of 1989, for instance.

It is often instigated as a means of re-establishing national security in the wake of uprisings or coups d’etat, as seen in Thailand in 2006 and 2014 and in Egypt in 2013.

In the case of Ukraine, a state of martial law has been declared for the first time since 1945 in 10 strategic border regions: five neighbouring Russia, two near Moldova’s breakaway Trans-Dniester region where Russia has a military presence and three along the Black Sea and Azov.

This will last for a period of 30 days, after President Poroshenko’s initial appeal for 60 was curtailed, in order to see off further “acts of aggression” from the Kremlin, including the possibility of a full-scale invasion. Ukraine, independent and Western-facing since the fall of the Soviet Union in 1991, is thought to be regarded as a threat to regional stability by the Kremlin.

Russia’s actions on Sunday prompted angry demonstrations on the streets of Kiev, prompting Mr Poroshenko to react.

Under martial law, the military would have the power to ban further protests and strikes and even call up ordinary citizens for national service, its authority in place from Wednesday 28 November to 27 December.

President Poroshenko’s original proposals for the terms of martial law, covering the whole country, were criticised by fellow MPs as representing a roll-back of the rights hard-won during the Maidan revolution of 2014 and as a transparent bid to shore up waning support ahead of next March’s elections – or delay the ballot entirely.

Protests break out after Russia seize Ukraine warships in 2018 Show all 32 1 /32 Protests break out after Russia seize Ukraine warships in 2018 Protests break out after Russia seize Ukraine warships in 2018 Activists of opposition parties burn flares during a rally demanding to break an agreement with Russia on the use of the Azov Sea and the Kerch Strait, in front of the parliament building in Kiev Reuters Protests break out after Russia seize Ukraine warships in 2018 Volunteers with the right-wing paramilitary Azov National Corps light flares during a rally on the snowy streets in front of the Ukrainian parliament in Kiev after Russia seized two of their armored artillery vessels and a tug boat in the Black Sea AP Protests break out after Russia seize Ukraine warships in 2018 Ukrainian Nationalists demand to break the diplomatic relations with Russia and nationalization of Russian property in Ukraine EPA Protests break out after Russia seize Ukraine warships in 2018 Ukrainian activists burn flares during their rally in front of Russian Consulate in Kharkiv EPA Protests break out after Russia seize Ukraine warships in 2018 Activists of opposition parties burn flares during a rally demanding to break an agreement with Russia on the use of the Azov Sea and the Kerch Strait, in front of the parliament building in Kiev, Ukraine November 26, 2018. REUTERS/Gleb Garanich GLEB GARANICH Reuters Protests break out after Russia seize Ukraine warships in 2018 Seized Ukrainian ships, small armoured artillery ships and a tug boat, are seen anchored in a port of Kerch Reuters Protests break out after Russia seize Ukraine warships in 2018 Volunteers with the right-wing paramilitary Azov National Corps brandish flares during a rally on the snowy streets in front of the Ukrainian parliament in Kiev, Ukraine, Monday, Nov. 26, 2018. Some hundreds of protesters from far-right party National Corps brandished yellow-and-blue flags with the Ukrainian national trident symbol, and a banner reading 'Don't back down!" . (AP Photo/Efrem Lukatsky) Efrem Lukatsky AP Protests break out after Russia seize Ukraine warships in 2018 The President of Ukraine, Petro Poroshenko, announced, on 25 November, at a meeting of the National Security and Defense Council that they will introduce martial law in Ukraine for a period of 60 days and appeal to the Parliament to consider the move Reuters Protests break out after Russia seize Ukraine warships in 2018 Russia seized two small-sized 'Berdiansk' and 'Nikopol' armored artillery boats. The 'Yany Kapu' tugboat has forcibly been stopped Reuters Protests break out after Russia seize Ukraine warships in 2018 Children from an orphanage volunteer to help the city defenders strengthen trenches on Ukraine's Army positions near the village of Rybatske 25 km from Mariupol AP Protests break out after Russia seize Ukraine warships in 2018 Volunteers with the right-wing paramilitary Azov National Corps light flares during a rally on the snowy streets in front of the Ukrainian parliament in Kiev, Ukraine, Monday, Nov. 26, 2018. Some hundreds of protesters from far-right party National Corps brandished yellow-and-blue flags with the Ukrainian national trident symbol, and a banner reading 'Don't back down!" (AP Photo/Efrem Lukatsky) Efrem Lukatsky AP Protests break out after Russia seize Ukraine warships in 2018 Policemen guard at Russian consulate during a protest action in the Black Sea Ukrainian city of Odessa AFP/Getty Protests break out after Russia seize Ukraine warships in 2018 epa07190805 Ukrainian Nationalists burn flares and smoke grenades during their rally in front of Parliament building in Kiev, Ukraine, 26 November 2018 as they demand to break the diplomatic relations with Russia and nationalization of Russian property in Ukraine. The President of Ukraine Petro Poroshenko at a meeting of the National Security and Defense Council on 25 November 2018 announced the decision to introduce martial law in Ukraine and to appeal to the Parliament to consider the move at an extraordinary meeting. It is about the introduction of martial law for a period of 60 days. The Ukrainian Parliament will convene for an extraordinary meeting at evening 26 November 2018. Russia has seized three Ukrainian vessels amid their leaving the Kerch Strait on 25 November 2018. The two small-sized 'Berdiansk' and 'Nikopol' armored artillery boats have come under enemy fire and are now dead in the water. The 'Yany Kapu' tugboat has forcibly been stopped. The vessels have been captured by special forces of the Russian Federation, the press service of Ukraine's Navy said on Facebook on Sunday evening. EPA/SERGEY DOLZHENKO EPA Protests break out after Russia seize Ukraine warships in 2018 Activists of Ukrainian far-right groups shout slogans during their rally in front of the Ukrainian parliament in Kiev on November 26, 2018, as they demand to set martial law in the country and to cut diplomatic relations with Russia. - Ukraine's military was on high alert and parliament was to vote on November 26 on a request from President to impose martial law for 60 days after Russian navy seized three Ukrainian ships off the coast of Crimea. (Photo by Sergei SUPINSKY / AFP)SERGEI SUPINSKY/AFP/Getty Images AFP/Getty Protests break out after Russia seize Ukraine warships in 2018 With relations still raw after Russia’s annexation of Crimea and its backing for a pro-Moscow insurgency in eastern Ukraine, the capture of three Ukrainian naval vessels risks pushing the two countries towards a wider conflict. Graphic explains how the naval incident unfolded on a map Graphic News Protests break out after Russia seize Ukraine warships in 2018 Activists of far-right parties burn flares in front of the parliament building in Kiev during a rally to support the Ukrainian navy Reuters Protests break out after Russia seize Ukraine warships in 2018 A Ukraine army APC moves toward on position at an undisclosed location in eastern Ukraine AP Protests break out after Russia seize Ukraine warships in 2018 Ukrainian Nationalists sign a banner with a slogan reading like 'Not retreat and not surrendering!' EPA Protests break out after Russia seize Ukraine warships in 2018 Activists of Ukrainian far-right groups hold flares during their rally in front of the Ukrainian parliament in Kiev on November 26, 2018, as they demand to set martial law in the country and to cut diplomatic relations with Russia. - Ukraine's military was on high alert and parliament was to vote on November 26 on a request from President to impose martial law for 60 days after Russian navy seized three Ukrainian ships off the coast of Crimea. (Photo by Sergei SUPINSKY / AFP)SERGEI SUPINSKY/AFP/Getty Images SERGEI SUPINSKY AFP/Getty Protests break out after Russia seize Ukraine warships in 2018 Activists glue Ukrainian flag on the fence of Russian consulate AFP/Getty Protests break out after Russia seize Ukraine warships in 2018 A volunteer with the right-wing paramilitary Azov National Corps during a rally on the snowy streets in front of the Ukrainian parliament in Kiev AP Protests break out after Russia seize Ukraine warships in 2018 Volunteers with the right-wing paramilitary Azov National Corps hold flares during a rally on the snowy streets in front of the Ukrainian parliament in Kiev, Ukraine, Monday, Nov. 26, 2018. Some hundreds of protesters from far-right party National Corps brandished yellow-and-blue flags with the Ukrainian national trident symbol, and a banner reading 'Don't back down!" (AP Photo/Efrem Lukatsky) Efrem Lukatsky AP Protests break out after Russia seize Ukraine warships in 2018 epa07190891 Ukrainian Nationalists attend their rally in front of Parliament building in Kiev, Ukraine, 26 November 2018 as they demand to break the diplomatic relations with Russia and nationalization of Russian property in Ukraine. The President of Ukraine Petro Poroshenko at a meeting of the National Security and Defense Council on 25 November 2018 announced the decision to introduce martial law in Ukraine and to appeal to the Parliament to consider the move at an extraordinary meeting. It is about the introduction of martial law for a period of 60 days. The Ukrainian Parliament will convene for an extraordinary meeting at evening 26 November 2018. Russia has seized three Ukrainian vessels amid their leaving the Kerch Strait on 25 November 2018. The two small-sized 'Berdiansk' and 'Nikopol' armored artillery boats have come under enemy fire and are now dead in the water. The 'Yany Kapu' tugboat has forcibly been stopped. The vessels have been captured by special forces of the Russian Federation, the press service of Ukraine's Navy said on Facebook on Sunday evening. EPA/SERGEY DOLZHENKO SERGEY DOLZHENKO EPA Protests break out after Russia seize Ukraine warships in 2018 An activist piles up tires during a protest against the seizure by Russian special forces of three of the Ukrainian navy ships, which Russia blocked from passing through the Kerch Strait into the Sea of Azov in the Black Sea, in front of the Russian embassy in Kiev, Ukraine November 25, 2018. REUTERS/Gleb Garanich Reuters Protests break out after Russia seize Ukraine warships in 2018 A National Guard serviceman extinguishes a torch thrown by a protester during a rally against the seizure by Russian special forces of three of the Ukrainian navy ships Reuters Protests break out after Russia seize Ukraine warships in 2018 A protester throws a smoke grenade during a rally in front of the embassy of Russia in Kiev AP Protests break out after Russia seize Ukraine warships in 2018 Protestors set up paper ships on the tires during their rally near of Russian embassy building in Kiev EPA Protests break out after Russia seize Ukraine warships in 2018 Smoke from a flare thrown by a protester is seen during a rally against the seizure by Russian special forces of three of the Ukrainian navy ships, which Russia blocked from passing through the Kerch Strait into the Sea of Azov in the Black Sea, in front of the Russian embassy in Kiev, Ukraine November 25, 2018. REUTERS/Gleb Garanich GLEB GARANICH Reuters Protests break out after Russia seize Ukraine warships in 2018 A man extinguishes a burning car of the embassy of Russia Reuters Protests break out after Russia seize Ukraine warships in 2018 Paper boats are seen placed during a protest Reuters Protests break out after Russia seize Ukraine warships in 2018 epa07190225 Ukrainian policemen guard the Russian embassy building with smoke behind during Ukrainian activists rally in Kiev, Ukraine, 25 November 2018. Russia has seized three Ukrainian vessels amid their leaving the Kerch Strait; Ukrainian President Petro Poroshenko is gathering the Military Cabinet over the incident. The two small-sized 'Berdiansk' and 'Nikopol' armored artillery boats have come under enemy fire and are now dead in the water. The 'Yany Kapu' tugboat has forcibly been stopped. The vessels have been captured by special forces of the Russian Federation, the press service of Ukraine's Navy said on Facebook on Sunday evening. The Ukrainian Navy also reported the number of the Ukrainian servicemen wounded in the incident grew to two persons as Ukrainian media report. EPA/STEPAN FRANKO EPA-EFE/STEPAN FRANKO EPA Protests break out after Russia seize Ukraine warships in 2018 epa07190217 A protestor throws a smoke grenade at the building during their rally near the Russian embassy in Kiev, Ukraine, 25 November 2018. Russia has seized three Ukrainian vessels amid their leaving the Kerch Strait; Ukrainian President Petro Poroshenko is gathering the Military Cabinet over the incident. The two small-sized 'Berdiansk' and 'Nikopol' armored artillery boats have come under enemy fire and are now dead in the water. The 'Yany Kapu' tugboat has forcibly been stopped. The vessels have been captured by special forces of the Russian Federation, the press service of Ukraine's Navy said on Facebook on Sunday evening. The Ukrainian Navy also reported the number of the Ukrainian servicemen wounded in the incident grew to two persons as Ukrainian media report. EPA/STEPAN FRANKO EPA-EFE/STEPAN FRANKO EPA

The president currently trails former prime minister, Yulia Tymoshenko, at the polls. His campaign slogan, incidentally, reads: “Army, Language, Faith”.

“Poroshenko wanted to use the situation in Kerch to grow his rating, to follow the example of Margaret Thatcher, who strengthened her position with the Falklands War of 1982,” opposition MP Sergii Leschenko commented, expressing concern about the future of civil liberties.

The president countered that there was “no reason for dirty speculation” as to his intentions.

On Monday, US president Donald Trump said: “We do not like what’s happening, either way we don’t like what’s happening and hopefully they’ll get straight.”

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German chancellor Angela Merkel was among the other world leaders adding their voices to the condemnation of Russia’s actions.