'Ukrainian conflict has escalated into war'

Ukrainian Defence Minister Valeriy Geletey Monday said the conflict in eastern Ukraine between government troops and pro-independence insurgents has escalated into a "war".

"A great war came at our doorstep, the war, which Europe has not seen since World War II," Geletey wrote on his official Facebook page, Xinhua reported.

Accusing Russia of beginning a "full-scale invasion" of Ukraine, Geletey announced the end of government's military operation in the east.

"The operation to liberate eastern Ukraine from 'terrorists' is over. We must urgently undertake the defence against Russia," Geletey said.

He blamed Moscow for the escalation of the conflict in Lugansk and Donetsk regions, claiming that Russia "via unofficial channels" has threatened to use "tactical nuclear weapons" against Ukraine.

Geletey estimated that the casualties in the "war" to be numbered in "thousands and even tens of thousands of people" and called for the "consolidation" of the Ukrainian society.

Earlier in the day, Russian Foreign Minister Sergei Lavrov said Moscow will not militarily interfere in the ongoing Ukraine crisis, urging the US and the European Union (EU) to help stop Kiev from using heavy weapons.

In mid-April, Ukraine's military launched offensives against insurgents to regain control over the seized cities and towns in eastern part of the country.

The armed conflict has claimed at least 2,500 lives and displaced thousands of people.