Ukraine on Thursday appealed to the UN Security Council to take action to oppose a decision by President Vladimir Putin to grant Russian passports to Ukrainians living in eastern areas controlled by pro-Moscow separatists.

Putin signed a decree allowing residents of the Donetsk and Lugansk regions to apply for Russian citizenship under a fast-track process that would deliver the passports within three months.

The decision came just days after the victory in presidential elections of Volodymyr Zelensky, who has called for more international sanctions against Russia over the move.

Ukrainian Ambassador Volodymyr Yelchenko told a council meeting that the decree was "simply illegal" and called for "real action," even if Russia would likely veto or block a measure opposing the decree.

Russian citizenship rights to Ukrainians amount to a "creeping annexation" of east Ukraine and "consolidation of the total Russian control over the occupied territories," he said.

"I call on this Council to prevent the worst scenario, to condemn resolutely the destructive and illegal actions of the Russian authorities and to restore the respect for the UN charter," Yelchenko said.

Western powers however pointed to Zelensky's election victory as an opportunity to relaunch talks with Moscow on ending the five-year conflict that has left some 13,000 dead.

"We think right now the emphasis should be on a renewed effort to implement the Minsk agreement and to bring peace to the people that are suffering under this crisis," German Ambassador Christoph Heusgen told reporters after the meeting.

The Minsk agreements, brokered in 2015 by Germany and France, were to lead to a political settlement but have stalled amid accusations from both sides of failing to live up to commitments.

During the council meeting, Heusgen pointedly told the Russian ambassador that Moscow could have greeted the new Ukrainian president with "rhetorical flowers" to show good will instead of the decree.

"It's too early for flowers," said Russian Ambassador Vassily Nebenzia, adding that Moscow was received contradictory signals from Zelensky and would judge him by his actions.

The United States said it was "unacceptable" for Russia to decide to extend citizenship rights to Ukrainians just after the election and accused Moscow of fueling the conflict.

French Ambassador Francois Delattre also took a swipe at Russia, saying "the solution to this crisis is not to hand out Russian passports to Ukrainian citizens" but to respect commitments made to end the conflict.