A new batch of satellite images have been released which allegedly prove Russia has built up thousands of troops on the Ukrainian border.
Nato released a series of images to media yesterday apparently depicting Russian military presence near Belogorod, Novocherkassk, Kuzminka, Yeysk and Butulinovka.
However, Kremlin officials cited in various media publications claimed the pictures were taken in 2013 and merely showed a military exercise being carried out at the time.
Nato's Supreme Headquarters Allied Powers Europe (SHAPE) has defended the accuracy of the pictures, however, and says the "claims of Russian officials are categorically false".
The new images show the same areas were unoccupied until March 2014, when tensions with Ukraine were escalating following the ousting of President Viktor Yanukovych.
Tensions remain high in eastern Ukraine after at least three died in a day of shooting during what was supposed to be an Easter truce.
In an exclusive interview with NBC News, the Ukrainian Prime Minister warns of the dangers of unchecked Russian expansion and aggression.
Russia, the US and the EU say that all sides have agreed to steps to "de-escalate" the crisis in Ukraine at talks in Geneva.