Ukrainian President Petro Poroshenko yesterday accused Russia of sending 9,000 troops to back separatist rebels in the east of his country, and the IMF chief said she backed extra financial help for Kiev as the conflict inflicts severe economic damage.

Moscow challenged Poro-shenko to present facts to prove his allegations. However, he won support from Nato, which said the amount of heavy military equipment used by Russian troops in eastern Ukraine had increased, and the alliance repeated its call for the forces to withdraw.

Speaking at the World Economic Forum in Davos, Poroshenko made one of Kiev’s boldest assertions yet that Russia’s military is directly involved in a conflict in which more than 4,800 people have died since last April.

If this is not aggression, what is aggression?

Russian troops were backed by a range of heavy weapons, including tanks, heavy artillery and armoured vehicles, he said, adding: “If this is not aggression, what is aggression?”

Poroshenko also called on Moscow to comply with a peace plan agreed in Minsk, Belarus, last September between Ukraine, Russia and pro-Russian separatist leaders to end the conflict.

“The solution is very simple – stop supplying weapons... withdraw the troops and close the border,” he said. “If you want to discuss something different, it means you are not for peace, you are for war.”

The Minsk plan provides for a ceasefire and the withdrawal of foreign fighters and military equipment from Ukraine. But the ceasefire has been very shaky from the start and hundreds of people have died since September in clashes Kiev says have involved regular Russian troops.

Russian Foreign Minister Sergei Lavrov tried to fend off the accusations, saying he hoped for progress at talks on the conflict on Wednesday despite the renewed fighting.

“If you allege this so confidently, present the facts. But nobody can present the facts, or doesn’t want to,” Lavrov told a news conference before heading to the peace talks in Berlin with the foreign ministers of Ukraine, Germany and France.

German Chancellor Angela Merkel, however, warned against expecting too much from the talks.

“I don’t want to get hopes up too much,” she said. “It is clear that the ceasefire is getting more and more fragile.”

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