The Russians demanded that the approximately 150 Ukrainian soldiers leave the base, one of Ukraine’s biggest in Crimea. The Ukrainian commander of the base, Colonel Yuliy Mamchur, told his men to put their weapons in the base’s armory, the Associated Press reported.

The assault, which wounded at least one Ukrainian soldier, appeared to be an attempt by Russia to solidify its hold on Crimea after its formal annexation of the region.

BELBEK, Crimea — Russian forces in armored vehicles on Saturday smashed through the gates of one of the last military bases in Crimea still controlled by Ukrainians, firing shots into the air, surrounding the soldiers, and demanding their surrender.


The news came amid high tensions in Crimea, after a referendum last weekend in which residents, under the watch of Russian soldiers who had already moved into the region, voted to secede from Ukraine.

A spokesman for the Ukrainian military in Crimea said Russian troops earlier Saturday had taken a base at Novofyodorovka, near the city of Saki, about 30 miles west of Simferopo.

In recent days, Russian forces have taken over other bases in Crimea without casualties.

Also Saturday, there were reports of tension in eastern Ukraine, with demonstrations in at least two cities where pro-Russian protesters demanded a similar referendum to the one held in Crimea on March 16.

More than 5,000 pro-Russia residents of Donetsk demonstrated in favor of holding a referendum on whether to split off and become part of Russia.

Earlier in the day, Moscow appeared to try to assuage international worries that its aggression would not stop in Crimea, endorsing the deployment of 100 international monitors to places in Ukraine outside Crimea.

Fears of an incursion into Ukraine had been rising Friday as Russian troops were massed along the border. The Russians have said the troops are there for training exercises.


The announcement from the Russian Foreign Ministry about the monitors underlined that Crimea remained outside the mandate of the observer team approved by the Organization for Security and Cooperation in Europe.

The Russian statement said excluding Crimea “reflects the new political-legal realities” because it has “become part of Russia.”

Still, it seems unlikely Russia would agree to an international observer mission if it was planning to pour troops over the border into eastern Ukraine, where demands for greater autonomy from Kiev or even annexation with Russia have emerged among a large population of Russian speakers.

“Russia hopes that unbiased and impartial work of international observers would help overcome the internal Ukrainian crisis,” the Foreign Ministry said.

Russia maintains that it was forced to intervene in Crimea to protect the Russian-speaking population, which forms a majority in the territory that was part of Russia until 1954.

The Russian statement called on the observer mission to help eradicate “radical” elements.

The final agreement among the 57-member Organization for Security and Cooperation in Europe, based in Vienna, came late Friday after Russia lifted its objections.

But the US Mission issued a statement saying it still considered Crimea part of Ukraine, noting that only Russia disagreed.

The statement from the Foreign Ministry called the negotiations “complicated.” The wording of the final accord was left rather ambiguous, listing various geographic areas but not Crimea. Last week, Russian forces prevented OSCE military observers from entering Crimea.

The first civilian observers were expected to arrive by Saturday night and Sunday, said Tatyana Baeva, a spokeswoman for the international group, via e-mail. The full contingent, to be recruited from member states, will arrive in Ukraine over the next week, she said.


The agreement among member states established the OSCE Special Monitoring Mission for six months, saying it could grow to 500 members if needed.

Its main task is to observe the security situation and to report on specific incidents.

With Crimea now effectively under the control of Russian forces, concern is rising that Ukraine’s eastern regions will agitate for a similar move.

The local Parliament in Donetsk formed a working group Friday to develop a secession referendum analogous to the one in Crimea.