File photo of President Petro Poroshenko.
Belarus said that a new round of Ukrainian peace negotiations involving the warring sides and overseen by European and Russian envoys would be held on Friday in Minsk.
"The Contact Group on Ukraine has informed the Belarussian side of its intention to hold its next meeting in Minsk on January 30," the Belarussian foreign ministry said in a statement.
The announcement came moments after Ukrainian President Petro Poroshenko called for urgent truce talks with pro-Russian rebels to end a bloody surge in fighting in the separatist east.
Poroshenko said a new Minsk meeting should lead to "an immediate ceasefire and the withdrawal of heavy weapons from the line of contact" established in a repeatedly broken September truce.
Two earlier sets of Minsk agreements called for the creation of a 30-kilometre (18-mile) buffer zone between the warring sides' armies and allowed international monitors to oversee the deal's implementation.
The talks were overseen by the Organization for Security and Co-operation in Europe (OSCE) and also involved Moscow's ambassador to Kiev -- the same group due to meet on Friday in Minsk.
Separatist leaders last week had formally pulled out of peace negotiations and announced the launch of a new offensive aimed at expanding their area of control.
The last Minsk meeting on December 24 failed to achieve any progress and was soon followed by new fighting.
Kiev was irritated on that occasion by the decision of the self-declared leaders of the Donetsk and Lugansk rebel regions to send lower-level officials to the talks.
Donetsk co-leader Andrei Purgin told AFP that his separatist region would be sending a lower-level negotiator named Denis Pushilin to Friday's talks as well.
"If tomorrow's meeting in Minsk does go ahead, then of course we will take part. But I would not bet on it because such meetings failed to materialise in the past," Purgin said by telephone.
Poroshenko said the negotiations should also establish a reinforced OSCE presence along the Russian-Ukrainian border to make sure no weapons or reinforcements reach the rebels from the east.
Russia denies backing the nine-month revolt.
But eastern European nations accuse Russian President Vladimir Putin of trying to stamp his countrol over countries that answered to Moscow in the Soviet era or were part of the tsarist empire.
Poland's defence minister said he believed the chances of a breakthrough in Minsk were slim because the Kremlin main goal was to undermine the talks.
"Russia's obvious goal is to block Ukraine's path toward Europe," Tomasz Siemoniak told reporters in Warsaw.