Kiev accused Russia on Friday of sending more tanks and troops into eastern Ukraine and said they were heading towards the rebel-held town of Novoazovsk on the southern coast, expanding their presence on what could be the next key battlefront.
Russia did not immediately respond to the accusation which, if confirmed, would be almost certain to finally kill off a tattered European-brokered truce that came into force on Sunday. Moscow has always denied such charges in the past.
Novoazovsk lies on the Sea of Azov and was captured by rebels last year and could be a launching-pad for more pressure on Mariupol, a gateway to the south and possibly to the Crimea peninsula annexed by Russia a year ago.
“In recent days, despite the Minsk (ceasefire) agreement, military equipment and ammunition have been sighted crossing from Russia into Ukraine,” military spokesman Andriy Lysenko said.
He said more than 20 Russian tanks, 10 missile systems and busloads of troops had crossed the border into Ukraine.
Western nations have clung to the hope that they can revive the peace deal brokered by France and Germany in the Belarussian capital Minsk on Feb 12 even though the rebels ignored it to seize the important railway hub of Debaltseve.
The German, Russian, Ukrainian and French foreign ministers are expected to meet next week to pursue peace moves. But hopes were slim even before the latest sighting of Russian reinforcements, also reported by the United States this week.