Ukrainian President Petro Poroshenko on Thursday called on Russia to support his peace plan "with deeds, not words" as a weeklong cease-fire between government troops and pro-Russian rebels is set to expire late Friday.
German Chancellor Angela Merkel and US secretary of state John Kerry said they too were looking for more action from Russia ahead of a summit on Friday of European Union leaders who will be reviewing their sanctions against Moscow.
More than 300 people have been killed in eastern Ukraine in the past weeks as pro-Russian insurgents fought with government forces. Ukraine last Friday announced a unilateral cease-fire with the rebels. Some rebel groups said they would observe the cease-fire as well.
Even so, 18 government troops have been killed this week, Poroshenko said.
Speaking at the Parliamentary Assembly of the Council of Europe in Strasbourg on Thursday, Poroshenko called for Moscow to support his peace plan with deeds and, specifically, prevent armed separatists from crossing the Russian border into Ukraine.
"Without that, we cannot talk about peace," Poroshenko said. "Do support the peace plan with deeds, not words, because with these deeds we will stop the killing of civilians and the military who defend the sovereignty and territorial integrity of the state."
Kerry, speaking in Paris, said "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."
EU leaders will be meeting Thursday evening in Ypres and Friday in Brussels, and will weigh the need to impose new sanctions on Russia over its actions in Ukraine. EU officials have said tougher economic sanctions have been prepared and are ready for use.
Merkel also stressed the importance for Russia to show its commitments "in the coming hours," saying that Germany will "have to decide how we will further proceed" on possible sanctions against Russia after a meeting with Poroshenko on Friday.
Russian President Vladimir Putin has said he supports the plan. This week he won agreement from the upper chamber of the parliament to cancel authorization for the use of force in Ukraine.
Putin and Merkel had a telephone conversation on Thursday, discussing "the need to extend the cease-fire" in Ukraine and release people held by armed rebels in eastern Ukraine, the Kremlin said.
Poroshenko also announced that representatives of the mutinous regions have agreed to sit down to talks with the Russian ambassador, a former Ukrainian president representing Poroshenko, and an OSCE envoy. The first round of these talks was held on Monday, bringing rebel leaders to the negotiating table for the first time.