Ukraine crisis: Russia 'has crossed a red line'
13 May 2014 Last updated at 19:07 BST
Ukrainian Prime Minister Arseniy Yatsenyuk has accused of Russia wanting to make Ukraine "a failed state" and called for tougher sanctions against Moscow.
Speaking to the BBC, Mr Yatsenyuk said Russia had "crossed red lines" and that it was "high time" for action.
On Sunday self-rule referendums were held in the Donetsk and Luhansk regions. Kiev called the polls a "criminal farce" organised by Russia.
The Ukrainian government fears a similar outcome to the annexation of Crimea in Donetsk, Luhansk and parts of the south.