More than 80 unmarked military vehicles have been seen on the move in rebel-controlled areas of eastern Ukraine, indicating that intensified hostilities may lie ahead.

Three separate columns were seen by Associated Press reporters today, one near the main separatist stronghold of Donetsk and two outside the town of Snizhne, 50 miles further east.

The vehicles were mainly transportation trucks, some of them carrying small and large calibre artillery systems, and at least one armoured personnel carrier.

Ukrainian officials said this week that they believe rebel forces have received substantial consignments of weaponry and manpower from Russia. Moscow denies such claims.

Despite a ceasefire being reached in September, Ukrainian and rebel troops engage on a regular basis, with some of the heaviest fighting focused on Donetsk airport.