Ukraine official: separatists acting on Russia's orders

The two Russian-backed, self-proclaimed republics in Ukraine's Donetsk and Luhansk regions are at the centre of a surge in tensions between Moscow and the West over a vast Russian military buildup near Ukraine.

The OSCE's Special Monitoring Mission that is deployed in the conflict zone said it had logged 553 explosions in Donetsk.

A further 860 were reported in neighbouring Luhansk.

"This is part of their plan, I can say for sure, it follows a scenario. Scenario written in Moscow and they (the separatists) just follow it,"

Oleksii Danilov, Secretary of Ukraine's National Security and Defence Council said.

"For the past three days the front-line zones have been under fire. The enemy does all that is possible to force us to fire at populated areas by positioning the artillery in between buildings inhabited by people. All in order to then accuse us of genocide, of killing the people of Donbas," commander of the joint forces Oleksandr Pavliuk accompanying Danilov on his trio said.

Western countries have said they think the shelling, which began on Thursday and intensified since, could be part of an attempt by Russian President Vladimir Putin's government to create a pretext to justify an attack on Ukraine.

Russia says it has no such intention and accuses the West of irresponsible fear-mongering.