Former US President Bill Clinton has called upon Russia to stop interfering in Ukraine and allow it to determine its own future.
Speaking at the Global Education & Skills Forum 2014 in Dubai, Clinton conceded that the result of the 'phoney' Crimea referendum aligning it with Russia was historically correct.
He said: "Crimea is a special case because Krushchev gave it to Ukraine in '52 thinking Moscow would always run the whole show."
But Mr Clinton denounced the recent vote in Crimea as an "unconstitutional farce. [Putin's] storyline that he has created that these poor Russians are being crushed by these ultranationalist Ukrainians, is just not so."
The former US president revealed that in private Vladmir Putin was a straight-talker. "You can normally work with someone like that, and I just hope and pray that this thing is not going to spin out of hand because Ukraine is an important country. All [the Ukrainians] wanted was the right to determine their own future and they should have it."
Mr Clinton went on to warn Putin that his brinkmanship was setting a perilous course and inviting a dangerous end-game.
"If he wants to keep pushing the envelope and going in and out of Eastern Ukraine, I don't know what's going to happen. It's a very dangerous situation and it's unnecessary, and it's going to in the end hurt Russia more than it helps Russia."
In a startling personal assessment of Putin's political values, America's former head of state told the Dubai meeting of global leaders and top educators that Putin considered ordinary human life as expendable in the pursuit of nationalist aims.
"He is highly intelligent, deeply, deeply patriotic in terms of Russia, but he sees it more in terms of the greatness of the State. I think he's got a sort of fatalistic view of the misfortunes that befall ordinary people when larger things are at stake," said Clinton.
Russia was seen as a "strong-man plutocracy" misusing its economic strength and intellectual depth, explained Mr Clinton, when it could be a global force for good, growth and technological advancement.
Violence in Donetsk
Within hours of Clinton's speech, hundreds of pro-Russian demonstrators stormed government buildings in Ukraine's eastern city of Donetsk.
At least 5,000 protesters marched through the city's Lenin Square, shouting "referendum, referendum", and then breaking into the local headquarters of Ukraine's security services and the prosecutor's office to demand that their self-appointed "governor" be freed.
Reports suggest two men clambered up onto the entrance of the security headquarters and tore down the Ukrainian flag, replacing it with a Russian flag featuring the words "Donetsk Republic".
Vans were smashed and books were burnt during the protests, which left several people, including at least one policeman, injured.