Nato's Supreme Headquarters Allied Powers Europe (SHAPE) has released satellite imagery that shows details of the location and type of Russian units near the Ukraine border.
Captured by commercial satellite imaging company DigitalGlobe last month, the photographs support Nato's assessment that the Russian military has amassed approximately 35,000 to 40,000 soldiers on the border.
SHAPE Comprehensive Crisis Operations and Management Centre (CCOMC) director brigadier Gary Deakin said Russia has lined up aircraft, helicopters, special forces, tanks, artillery and infantry fighting vehicles, which could move into Ukraine in a matter of hours.
"These forces have a destabilising effect and present serious implications for the security and stability of the region," Deakin said, noting that the Russian units are accumulating in various locations, rather than conducting specific exercises.
Nato Supreme Allied Commander Europe general Philip Breedlove said: "I would characterise it as a combined arms army... it has all of the provisioning and enabling that it needs to accomplish military objectives, if given them."
However, an unnamed Russian Army general staff official told RIA Novosti that the photographs were taken in August 2013.
"These shots, which were distributed by Nato, show Russian Armed Forces units of the southern military district, which in the summer of last year were taking part in various drills, including near the Ukrainian border," the official said.
Russia has repeatedly denied troop build up near the Ukrainian border, and has warned that any deployment of Nato troops near Russia's borders would be a violation of international agreements.
Nato has confirmed that it is closely monitoring events and has increased airborne warning and control system (AWACS) surveillance flights over Romania and Poland in order to maintain awareness of activity in Ukraine.
In addition, the alliance has significantly increased air-policing activity and the number of aircraft dedicated to this mission.
Image: The alleged Russian artillery battalion near Novocherkassk, Rostov Oblast, Russia. Photo: courtesy of DigitalGlobe.