Ukrainian paratroopers with armoured vehicles were digging in on Thursday near the Russian border as the military demonstrated its presence in the east following Kiev's loss of Crimea to Moscow's forces, Reuters reported. The soldiers, camped in tents with some two dozen trucks and BMD-1 combat vehicles, would not discuss their mission. They set up sandbags, strung barbed wire and carried out infantry drills in small groups next to a small quarry in rolling grain country, 30 km (20 miles) from the Russian border in Donetsk region. Ukraine's government has put its heavily outnumbered and outgunned forces on alert for an invasion from Russia in the east following Moscow's seizure of the Black Sea peninsula. But there is little evidence of a major Ukrainian troop build-up.