Russian troops attempted to storm a Ukrainian missile base in Sevastopol on Friday night but were thwarted when the defenders barricaded themselves inside.
Stun grenades were said to have been thrown by the attackers who used a military truck to drive through the gates to the base but no shots were fired.
About 100 Ukrainian troops are thought to have been in the missile installation and the Russians left after holding talks with the base commanders and reaching an agreement with them. Estimates of the number of Russians involved ranged from 20 to 60.
It remained unclear why the Russians tried to enter the base, what their intentions were or what agreement they came to with the Ukrainian officers.
The Ukrainian deputy commander spoke briefly to journalists afterwards and said the Russians had told him they had permission to open fire.
Several members of a pro-Russian “self-defence” militia were also seen outside the base and were said to have attacked two press photographers who tried to take pictures of the scene.
The standoff came at the end of a day when Russia appeared to have tightened its grip on the Crimean peninsula with an estimated 20,000 of its troops now based in the region. The estimate by the Pentagon was 10,000 lower than that of a Ukrainian figure cited earlier today.
Moscow’s strained relations with Western nations continued to fester as it issued warnings that sanctions or other measures imposed by the United States or the European Union would provoke retaliation.