Fulfil Moscow's demands, 'otherwise, the issue will be decided by the Russian army', Russia's foreign minister said.

Russian Foreign Minister Sergey Lavrov has given Ukraine an ultimatum: Fulfil Moscow's demands — including surrendering Ukrainian territory that Russia now controls — or the Russian army will decide the fate of Ukraine.

Speaking a day after Russian President Vladimir Putin once again said he was open to peace talks — and which the United States has described as disingenuous — Lavrov told Kyiv that it should, for its "own good", comply with Moscow's wishes.

"Our proposals for the demilitarisation and denazification of the territories controlled by the regime, the elimination of threats to Russia's security emanating from there, including our new lands, are well known to the enemy," state news agency TASS quoted Lavrov as saying late on Monday.

"The point is simple: Fulfil them for your own good. Otherwise, the issue will be decided by the Russian army," Lavrov said.