KIEV (AFP) - The government in Kiev said Thursday that Russia had massed around 4,000 troops stationed in annexed Crimea on the border with Ukraine.

"According to our information, almost all military units of the Russian Federation stationed in the north of occupied Crimea... were pushed to the administrative border with Ukraine along with all their equipment and ammunition," National Security and Defence Council spokesman Andriy Lysenko told reporters.

He said the units, totalling about 4,000 troops, were deployed in "small tactical groups" along the estimated 100-kilometre border in Crimea, which Russia annexed in March.

Russia's Defence Minister Sergei Shoigu said earlier this week that Moscow planned to boost troop numbers in Crimea because of what he described as a deteriorating situation in Ukraine and a buildup of foreign troops near its border.

Russia is deeply concerned at Nato's move eastwards and President Vladimir Putin has accused the West of provoking the crisis in Ukraine in order to "revive" the military bloc.

Nato this month agreed to boost its presence in eastern Europe, and the United States is currently staging war games in western Ukraine along with another 14 countries.

Russia's Black Sea fleet is based in Crimea and Moscow announced in July that it had begun expanding and modernising it with new ships and submarines.

In weekend elections, Putin's ruling United Russia Party won more than 70 per cent of the vote in Crimea's regional parliament, a poll the United States rejected as illegitimate.