President of Ukraine Petro Poroshenko has said between 500 to 1,000 militants, including a number of armored vehicles, attacked Ukrainian Armed Forces positions near Maryinka on Wednesday.

"On June 3 we faced assault actions involving from 500 up to 1,000 of [militants] personnel with an essential number of tanks, armored vehicles, who hoped on the effect of suddenness so that to promptly seize Maryinka," he said at a press conference in Kyiv on Friday.

Poroshenko said "it is not surprising that the militants' attempt to provoke an escalation of the conflict took place simultaneously with the threats to allow the use of Russian troops in Ukraine, that it, to retroactively legitimize what has been going on in Ukraine for a year now."

"The Russian supreme command may have lost contact with its own army and may not know that it has left the territory of Russia and got 'lost' in the steppes of Donbas. The whole Russian military arsenal, except maybe for submarines, is present there," Poroshenko said.