Ukraine offers amnesty to pro-Russian separatists
Ukraine will not prosecute pro-Russian activists occupying official buildings in two eastern cities if they surrender their weapons, Ukraine's acting President Olexander Turchynov says.
The separatists are holding buildings in the cities of Luhansk and Donetsk. The Kiev authorities say their actions could give Russia a pretext to invade.
Ukraine has accused Russia of stirring up the unrest. Moscow has denied that.
Nato says up to 40,000 Russian troops are massed near Ukraine's border.
The crisis began in November when Ukraine's former President Viktor Yanukovych - an ally of Russia - refused to sign a far-reaching partnership treaty with the EU. That triggered huge anti-Yanukovych demonstrations and violence which led to him fleeing to Russia in February.
Ukraine has launched what it calls an "anti-terrorist operation" to tackle the separatists in the east. On Wednesday Kiev said the stand-off must end within 48 hours.
Mr Turchynov told parliament in the capital Kiev there would be "no criminal prosecution of people who give up their weapons and leave the buildings".
"I am willing to do this by presidential order," he said.
Ukraine fears that the Russian separatist actions are a provocation similar to the protests that gripped Crimea days before Russian troops annexed the peninsula last month.
The separatists in the east - a mainly Russian-speaking region with close ties to Russia - are demanding referendums on self-rule. In Donetsk they have declared a "people's republic".
After pro-Russian forces spread out across Crimea last month the new authorities there held a referendum which Moscow said legitimised its return to Russia. But the referendum was denounced internationally.
On Wednesday US Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov agreed on the need to resolve the security situation in eastern Ukraine peacefully, officials said.
The EU, Russia, US and Ukraine are to meet next week for talks on the crisis.
In Donetsk the separatists have built huge barricades outside the 11-storey regional administration building they are occupying. They stormed the building on Sunday.
Donetsk is the heartland of support for Mr Yanukovych, the city where he built his career in Soviet times. The region is dominated by coal-mining and heavy industry.
In Luhansk separatists are holding the local headquarters of the SBU state security service.
Meanwhile, European MPs in the Council of Europe - the continent's top human rights watchdog - have overwhelmingly condemned the Russian annexation of Crimea and the referendum there, in a strongly worded resolution.
"The drive for secession and integration into the Russian Federation was instigated and incited by the Russian authorities, under the cover of a military intervention," said the Parliamentary Assembly of the Council of Europe (PACE). Russia dismissed the resolution.
On Wednesday, Mr Kerry and Mr Lavrov "discussed the importance of resolving the security situation in key cities in eastern Ukraine peacefully and through dialogue and they both rejected the use of force to obtain political objectives," said US state department spokeswoman Jen Psaki.
Mr Kerry and Mr Lavrov spoke twice by phone on Wednesday about the eastern Ukraine tensions.
Mr Lavrov said next week's talks should focus on "dialogue among Ukrainians" and not on bilateral relations among the participants.
Mr Lavrov is expected to meet Mr Kerry, EU foreign policy chief Catherine Ashton and Ukraine's Foreign Minister, Andriy Deshchytsia.