Russian President Vladimir Putin has ordered troops into two rebel-held regions in eastern Ukraine, after recognising them as independent states. In a long, late-night televised address from the Kremlin, Mr Putin sought to justify his actions by making a series of claims about Ukraine. President Putin was talking about the Donbas region of eastern Ukraine, claiming Russian-speaking residents there are being subjected to "genocide" - a term he has used before, currently being echoed on Russian state television. The United Nations Genocide Convention, ratified by 152 countries, including Russia, defines genocide as "acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group". Examples include the killings in Rwanda and Srebrenica, it says. But there is no evidence of genocide in eastern Ukraine. And Mr Putin's claim has been dismissed by German Chancellor Olaf Scholz as "ridiculous". The UN says states "have sometimes characterised certain incidents or periods of violence as genocide" but these "characterisations cannot be treated as authoritative or determinative". There is a continuing conflict in eastern Ukraine, however. And in 2018, the International Crisis Group think tank found about 600,000 people - on both sides of the front lines - lived in unsafe settlements "where they are exposed daily to shelling, landmines, and tight restrictions on freedom of movement and basic services". Ukraine - which had the third biggest nuclear arsenal in the world during the Cold War - gave up its nuclear weapons in the 1990s in return for security guarantees from the US, UK and Russia. And it currently has no means of delivering nuclear weapons by air or any nuclear warheads that could be delivered by missiles, according to defence experts. Last year, the Ukrainian ambassador to Germany, Andriy Melnyk, suggested if Ukraine was unable to join Nato, it might have to reconsider its nuclear-free status. And this issue has reportedly become more prominent in public discussion following the conflict that erupted in eastern Ukraine and the Russian annexation of Crimea, in 2014. But the government has not said that it intends to return to having nuclear weapons and a revised military strategy published last year did not mention acquiring any. The UN's nuclear watchdog, the International Atomic Energy Agency (IAEA), told us that it had seen no signs in Ukraine "of the diversion of nuclear material, intended for peaceful activities, for other purposes."