The leaders of France and Germany are to press Ukraine's president to agree to a new truce in eastern Ukraine when they speak by phone on Wednesday.

President Francois Hollande of France announced the planned talks with Germany's Chancellor Merkel and Ukraine's President Petro Poroshenko.

Ukraine says it will not talk to separatist rebels until they disarm.

A separatist official in Donetsk city, where the rebels are regrouping after losing ground, ruled out any new truce.

Government forces recaptured several large towns from the rebels in recent days after resuming their "anti-terrorist operation" in the Donetsk and Luhansk regions.

In Donetsk itself, a city of more than one million people, the rebels have vowed to keep fighting the government, which they regard as illegitimate.

More than 1,000 people, both civilians and combatants, are believed to have been killed since the uprising began in April