The Ukrainian military said on Saturday there was no let-up in a pro-Russian rebel offensive in east Ukraine with separatist forces trying to seize more territory before a ceasefire comes into force at midnight.
Leaders of Russia, Ukraine, France and Germany on Thursday emerged from marathon 16-hour talks to announce a comprehensive peace deal for eastern Ukraine, but questions remained whether Ukraine and the pro-Russian rebels have agreed on all of its terms.
German Chancellor Angela Merkel said Thursday she had "no illusions" after a Ukraine ceasefire deal hammered out at marathon talks in Minsk and that "big hurdles" remained in ending the 10-month conflict in the ex-Soviet country.
A summit between France, Germany, Russia and Ukraine is being planned for Wednesday in Minsk, the latest step in a hectic diplomatic effort to find a political solution to the Ukraine conflict, Berlin said.
Russian President Vladimir Putin is behaving like a "mid-20th century tyrant", British Foreign Secretary Philip Hammond said on Sunday, urging him to change track and save Russia's economy from further decline.
Russian President Vladimir Putin said he was working towards peace talks with the leaders of France, Germany and Ukraine in Minsk on Wednesday but the four still need to agree on a "number of points" by then.
The leaders of Russia, Ukraine, Germany and France agreed to meet in Belarus on Wednesday to try to broker a peace deal for Ukraine amid escalating violence there and signs of cracks in the transatlantic consensus on confronting Vladimir Putin.
Ahead of their first official meeting, Special Representatives of India and China for border negotiations met in Munich during which the Chinese official called for pushing forward talks to resolve the border issue and remove "disturbances" in bilateral ties.