Russian foreign minister Sergei Lavrov called on Ukraine to distance itself from what he called "extremists" in the east and pursue a course towards peace. He said "tangible progress" had been achieved in implementing measures agreed in Minsk this month and that the ceasefire was being "consolidated".
Economic sanctions against Russia should be extended and toughened if Russian President Vladimir Putin does not pull back from Ukraine, the Prime Minister has said.
Speaking at a liaison committee meeting, David Cameron said if "miraculously" Russia withdrew its weapons and upheld ceasefires, the sanctions would be lightened - but in the meantime, he said the UK, US and Europe had to take a stand against his actions.
Mr Cameron said the sanctions were necessary to protect Moldova and the Baltics from being destabilised next.
He also criticised "serious" violations of British airspace by Russian craft, but said the UK was "more than capable" of defending itself.
Thousands of Russians are marching in Moscow to mark the first anniversary of what they viewed as a "coup" in neighbouring Ukraine.
14 soldiers died and many more were injured as Ukraine left the strategically important hub of Debaltseve.
Dramatic footage shows the moment a TV crew were forced to flee a huge explosion after a gas pipeline was hit by mortar fire in Ukraine.