Ukrainian President Petro Poroshenko has claimed Russia has more than 9,000 soldiers and 500 tanks, heavy artillery and armoured personnel carriers in eastern Ukraine.
He urged Moscow to withdraw its troops from the region and meet the terms of a ceasefire plan amid rising tension between Ukrainian troops and rebels in the east, reported the BBC.
Russia has categorically denied the presence of its troops and claims that said it was supporting separatists in the Donetsk and Luhansk regions.
Talks to control the crisis are going on in Berlin. Foreign ministers from Ukraine, Russia, France and Germany are expected to attend the meeting in the German capital.
More than 4,800 people have died and nearly 1.2 million have been displaced after rebels seized control over parts of Luhansk and Donetsk regions in April.
