Following a meeting with his French counterpart on Thursday, the United States' top diplomat, John Kerry, narrowed the deadline for Russia to prove it was upholding its international commitments in Ukraine.

"We are in full agreement that it is critical for Russia to show in the next hours, literally, that they're moving to help disarm the separatists, to encourage them to disarm, to call on them to lay down their weapons and to begin to become part of a legitimate process," Kerry said in Paris, where he had met with French Foreign Minister Laurent Fabius.

The US, European Union leaders and NATO have all expressed dissatisfaction at Russian President Vladimir Putin's failure to bring clashes in eastern Ukraine to an end. While Putin has said he supports Ukrainian President Petro Poroshenko's ceasefire and the intent of a peace plan, the Western leaders accuse him of remaining supportive of the pro-Russian separatists.

"Our preference is not to have to be [in] sanctions mode," Kerry said, referring to fresh warnings this week of slapping further bans on Putin allies and Russian companies linked to the unrest.

"[But] we all agree that [sanctions] need to be ready," he added.

EU ministers were gathering in the Belgian town of Ypres on Thursday for the start of a two-day summit. Kerry said that Moscow's actions in Ukraine would be discussed before the end of the day.

On Wednesday, the Russian parliament cancelled a March 1 authorization which allowed Putin to deploy troops to Ukraine. The decision was made in response to his personal request, filed the previous day.

However, NATO Secretary General Anders Fogh Rasmussen downplayed the significance of the Doma's decision given continued clashes in Ukraine. He indicated that the Western military alliance would be reviewing its relations with Moscow in order to determine how to proceed.

kms/pfd (AFP, Reuters)