KIEV — Pro-Russian crowds seized two Ukrainian warships Thursday and Ukraine said its troops were being threatened in Crimea, which was annexed by Russia this week in a move called illegal and unacceptable by Western powers.
Tensions in the region remained high despite the release of a Ukrainian naval commander held by pro-Russian forces.
Shots were fired but there were no casualties as the Ukrainian corvette "Khmelnitsky" was seized in Sevastopol, according to an AP photographer at the scene. Another ship, the "Lutsk," was also surrounded by pro-Russian forces.
The Defense Ministry had no immediate information on the incidents.
Ukraine's Deputy Defense Minister Leonid Polyakov accused Russian troops of constantly threatening to storm military bases where Ukrainian soldiers were located, according to Interfax.
In Geneva, Ukraine's ambassador to the United Nations warned of a sharp deterioration in relations between the two neighbors, saying that Russia appears to be preparing for a military "invasion" in more areas of his country.
Ambassador Yury Klymenko said there were "indications that Russia is on its way to unleash a full-blown military invention in Ukraine's east and south" since its annexation of Crimea. He said his statement was based on information from nongovernmental organizations.
In Crimea, the commander of Ukraine's Navy was freed after being held by Russian forces and local militia at the Navy's headquarters.
Rear Admiral Sergei Haiduk and an unspecified number of civilians were held for hours after the Navy's headquarters in Sevastopol was stormed Wednesday. Acting Ukrainian President Oleksandr Turchynov, who confirmed the release, said Russian forces were involved in the storming.
In response, Ukraine on Wednesday said it would hold joint military exercises with the U.S. and Britain, signatories, along with Russia, of the 1994 Budapest Memorandum — a document designed to guarantee Ukraine's territorial integrity when it surrendered its share of Soviet nuclear arsenals to Russia after the Soviet Union broke up in 1991.
With thousands of Ukrainian soldiers and sailors trapped on military bases, surrounded by heavily armed Russian forces and pro-Russia militia, the Kiev government said it was drawing up plans to evacuate its outnumbered troops from Crimea back to the mainland and would seek the UN's support to turn the peninsula into a demilitarized zone.
Since Russian forces took charge in Crimea, Ukrainian-enlisted personnel and officers have been bottled up in barracks and other buildings at one end of the Belbek airbase in the wine-growing country near Crimea's southwestern coast, with the Russians in control of the airfield.
"We are waiting for what Kiev, our leadership, tells us," said one major, who declined to give his name. The major said he expected about half of the personnel still at the base to accept the Russian offer to stay and join the Russian armed forces, since they were Crimea natives.
Humbled but defiant, Ukraine lashed out symbolically at Russia by declaring its intent to leave the Moscow-dominated Commonwealth of Independent States, a loose alliance of 11 former Soviet nations. The last nation to leave the group was Georgia, which fought a brief war with neighboring Russia in 2008 and ended up losing two separatist territories.