Russia is reportedly assembling troops and weaponry near its border with Ukraine, raising threats of a full-scale invasion of the Crimean Peninsula.
The Ukraine National Security and Defence Council secretary Andriy Parubiy said the forces massing include more than 80,000 soldiers, up to 270 tanks, 180 armoured vehicles, 380 artillery systems, 18 multiple-launch missile systems, 140 combat aircraft, and 90 combat helicopters, as well as 19 warships and cutters.
"Critical is the situation not only in Crimea, but along the entire north-eastern frontier," Parubiy said. "In fact, Russian troop units are two or three hours of travel from Kiev."
Pictures of Russian armoured vehicles, including motorised infantry vehicles, tanks, as well as Grad BM-21 multiple rocket launch vehicles, on the move in regions close to the Ukrainian border, only adds to the invasion reports.
However, Russian Deputy Defence Minister Anatoly Antonov has denied any military buildup on its 1,250m border with Ukraine, and noted that the country had also accepted Kiev's request to conduct a surveillance flight over its territory to check for a threat.
"We have decided to allow such a flight," Antonov said. "We hope that our neighbours are assured that there is no military activity that threatens them on the border."
Both Russia and Ukraine are entitled to unarmed aerial surveillance flights over each other's territories in the framework of the Open Skies Treaty signed by 34 states parties in 1992.
The force buildup reports come as the Crimean Peninsula prepares for the 16 March referendum, dubbed illegitimate by the Ukraine Government, on joining the Russian Federation.
Both houses of the Russian Parliament have announced support for Crimea, which is claimed to been taken over by pro-Putin troops, if it votes to leave Ukraine and join the federation.
Meanwhile, G7 leaders have warned the Russian Federation 'to cease all efforts to change the status of Crimea contrary to Ukrainian law and in violation of international law' and threatened 'further action' if it seizes Crimea.