Russia's presidential spokesperson, Dmitry Peskov, has disclosed Moscow has presented Ukraine with a draft document outlining its demands at truce talks.

Peskov told reporters on Wednesday that the ball is in the Ukrainians' court, and Russia is waiting for a response.

At the same time, he said, "We've said it repeatedly that the rate of work of the Ukrainian side leaves a lot to be desired," and they "do not display great willingness to intensify the negotiations process."

The announcement comes as Russian troops are being accused of killing many civilians in the suburbs of the Ukrainian capital, Kyiv.

Ukraine has said it may abandon ceasefire talks as Russian forces are intensifying their assault on eastern Ukraine.

Ukrainian presidential adviser and negotiator Mykhailo Podolyak expressed willingness to study the draft document.

He said that Ukraine gave the Russian delegation proposals when the two sides met in Turkey in March, and that Russia studied them and gave counterproposals.

He added it is now Ukraine's turn to study the document based on political and legal standpoints to reach a conclusion.