The deputy leader of a breakaway east Ukrainian region said he would take part in talks with representatives of Moscow and Kiev tomorrow but did not expect a breakthrough, Russia's Itar-Tass news agency reported.

Andrei Purgin, deputy prime minister of the rebels' self-proclaimed Donetsk People's Republic, told Tass the meeting of the so-called Contact Group in the Belarussian capital Minsk would be "only a first step in negotiations".

"The reference point has not changed," he said. "Each side will present the list of questions it is ready to discuss."

Presidents Vladimir Putin of Russia and Petro Poroshenko of Ukraine agreed last week to reconvene the Contact Group, which also includes the Organisation for Security and Cooperation in Europe (OSCE), in an effort to end the war in east Ukraine in which about 2,600 people have been killed.

But since their talks last Tuesday, the conflict has escalated, with pro-Russian separatists making gains along Ukraine's southeast coast. Kiev and its Western allies say the advance was made possible by Russian troops and tanks fighting inside Ukraine, something Moscow continues to deny.

Poroshenko said in Brussels yesterday he hoped for a ceasefire deal, warning that a failure to end the fighting in the coming days could lead to "full-scale war".

He said Ukraine would be represented in Minsk by a former president, Leonid Kuchma, and Russia by its ambassador to Ukraine, Mikhail Zurabov.