(Reuters) - Myanmar stands accused by rights groups of ethnic cleansing and human rights violations after violence broke out in the northwestern state of Rakhine, triggering an exodus of about 400,000 Rohingya Muslims to southern Bangladesh.  At least 400 people have been killed, and thousands of homes and villages have been torched, since the military launched a counteroffensive against Rohingya insurgents in late August. Myanmar does not recognize the roughly 1.1 million Rohingyas as citizens, leaving them effectively stateless. The following are questions and answers on the violence:     The military says it is protecting Myanmar against attacks by the Arakan Rohingya Salvation Army (ARSA), which it has labeled a terrorist group and accuses of killings and destruction in Rakhine state.  Human rights monitors and fleeing Rohingya say the army and ethnic Rakhine Buddhist vigilantes have mounted a campaign of arson aimed at driving out the Rohingya. Rights groups say an independent investigation is required to determine possible abuses or violations by various parties.     Yes, according to United Nations officials and rights groups.   Top U.N. officials have said the violence in Myanmar is a case of  textbook ethnic cleansing .   The U.N. has in the past defined ethnic cleansing as  rendering an area ethnically homogeneous by using force or intimidation to remove persons of given groups from the area.        Ethnic cleansing is not recognized as a separate crime under international law. But allegations of ethnic cleansing as part of wider, systematic human rights violations have been heard in international courts against individuals - including former Bosnian Serb leader Radovan Karadzic, who was convicted of genocide. Phil Robertson, deputy director for Asia at Human Rights Watch (HRW), said initial investigations in Myanmar were  indicative of an ethnic cleansing campaign .  When an army is burning people out of their villages all over northern Rakhine state and using violence against civilians, it results in the kind of incredible refugee flows we re seeing,  he added. Myanmar has denied allegations of ethnic cleansing. ARE WE SEEING GENOCIDE, WAR CRIMES, CRIMES AGAINST HUMANITY? Turkish President Tayyip Erdogan has said the killing of hundreds of Rohingya amounted to genocide, but rights groups have so far stayed away from these labels, because all three categories are clearly defined and covered in international law. For the ongoing violence to be considered war crimes, the parties involved would have to be at war. Currently, experts say, Myanmar is not technically at war because it only has one party - the military - that is organized enough to carry out intensive fighting operations.     We have not yet been able to determine whether a  state of war  is present in Rakhine state,  said HRW s Robertson.   Crimes against humanity and genocide could be taking place even in the absence of war, but, under U.N. definitions, there would need to be proof of other conditions such as broader,  systematic attacks against the Rohingyas.         Human rights groups have accused Myanmar of laying anti-personnel mines along the border with Bangladesh to prevent Rohingya refugees from returning to Rakhine state.  Because the crisis is not currently defined as a war, this cannot be considered a war crime, according to experts.  However it would violate other international human rights laws, even though Myanmar is not party to the 1997 Mine Ban Treaty.   For nations that are not parties to the treaty, the use of anti-personnel mines violates customary international law, because the weapons are inherently indiscriminate and cause disproportionate long-term harm to civilians,  said Richard Weir, a legal expert at HRW.  A Myanmar military source told Reuters that landmines were laid along the border in the 1990s to prevent trespassing and the military had since tried to remove them, but that none had been planted recently. In international law, an individual can be held criminally responsible for when a state or military commits war crimes or crimes against humanity. Rights groups have called for an independent investigation of abuses by all parties, including ARSA. Many believe the government and the military should be held responsible.   Myanmar is systematically violating the rights of the Rohingya ... and both the government and the military now need to suffer serious consequences for this,  said HRW s Robertson. This depends on the findings of an independent investigation, if the Myanmar government allows one to take place, experts say. Rights groups have called for the U.N. Security Council to also reprimand Myanmar in other ways, for instance, by imposing sanctions such as an arms embargo. They have also urged countries, including the United States and Australia, to suspend bilateral military ties. The 1991 Nobel Peace Prize winner has faced widespread international criticism for not doing enough to protect the Rohingya community. Suu Kyi has no direct control over the military, which remains powerful under Myanmar s army-written constitution. But she is Myanmar s foreign minister and de facto civilian leader and has defended the military operation.  It s premature to speculate,  said Robertson, adding that individual responsibility should be based on an impartial investigation.  The International Criminal Court (ICC), based in The Hague, Netherlands, has the jurisdiction to prosecute crimes of genocide, war crimes, and crimes against humanity.  Myanmar is among the countries, which also include the United States and China, that are not signatory to the treaty that created the ICC, so it is not obligated to cooperate. But if the U.N. Security Council were to refer a case to the court then Myanmar, being a member of the U.N., would be subject to its jurisdiction. Ad hoc tribunals and commissions have been set up in the past to hear cases of mass human rights violations. For instance, the United Nations established the International Criminal Tribunals for Yugoslavia and Rwanda to deal with crimes that took place there. Rights groups say they are protected by various U.N. human rights treaties, primarily the Universal Declaration of Human Rights, which Myanmar voted for in 1948. The document includes provisions for the right to life and right to a nationality - particularly relevant to the Rohingyas, who are effectively stateless. (Story amends headline.) 