Unidentified armed men patrol around a Ukraine's infantry base in Perevalne, Ukraine, Sunday, March 2, 2014. Hundreds of armed men in trucks and armored vehicles surrounded the Ukrainian military base Sunday in Crimea, blocking its soldiers from leaving. The outnumbered Ukrainians placed a tank at the base's gate, leaving the two sides in a tense standoff. (AP Photo/Darko Vojinovic)

A Russian flag flies in the foreground as unidentified armed men in uniform block a Ukrainian military base near the village of Perevalne, 20 km south of Simferopol, on March 2, 2014. A group of 1,000 armed men were blocking the entrance to a unit of Ukraine's border guards in a tense standoff in the south of the flashpoint Crimea peninsula on March 2, the defence ministry said. "One thousand armed fighters and around 20 trucks are blocking the perimetre of the 36th brigade of border guards... in Perevalne," the ministry said in a statement, as tensions remain high after Russia's parliament approved the deployment of troops in Ukraine. It did not indicate what nationality the armed men were. AFP PHOTO/ GENYA SAVILOV

Unidentified armed men in uniform block a Ukrainian military base near the village of Perevalne, 20 km south of Simferopol, on March 2, 2014. A group of 1,000 armed men were blocking the entrance to a unit of Ukraine's border guards in a tense standoff in the south of the flashpoint Crimea peninsula on March 2, the defence ministry said. "One thousand armed fighters and around 20 trucks are blocking the perimetre of the 36th brigade of border guards... in Perevalne," the ministry said in a statement, as tensions remain high after Russia's parliament approved the deployment of troops in Ukraine. It did not indicate what nationality the armed men were. AFP PHOTO/ GENYA SAVILOV

Two civilians stand by as unidentified armed men in uniform block a Ukrainian military base near the village of Perevalne, 20 km south of Simferopol, on March 2, 2014. A group of 1,000 armed men were blocking the entrance to a unit of Ukraine's border guards in a tense standoff in the south of the flashpoint Crimea peninsula on March 2, the defence ministry said. "One thousand armed fighters and around 20 trucks are blocking the perimetre of the 36th brigade of border guards... in Perevalne," the ministry said in a statement, as tensions remain high after Russia's parliament approved the deployment of troops in Ukraine. It did not indicate what nationality the armed men were. AFP PHOTO/ GENYA SAVILOV

Unidentified gunmen wearing camouflage uniforms block the road toward the military airport at the Black Sea port of Sevastopol in Crimea, Ukraine, Saturday, March 1, 2014. The pro-Russian prime minister of Ukraine's restive Crimea is claiming control of all military forces, police and other security services in the region. In a statement reported by local and Russian news agencies on Saturday, Sergei Aksenov declares that the armed forces, the police, the national security service and border guards will answer only to his orders. He says that any commanders who don't agree should leave their posts. (AP Photo/Darko Vojinovic)

An unidentified gunman wearing camouflage uniform stands guard and block the road toward the military airport at the Black Sea port of Sevastopol in Crimea, Ukraine, Saturday, March 1, 2014. The pro-Russian prime minister of Ukraine's restive Crimea is claiming control of all military forces, police and other security services in the region. In a statement reported by local and Russian news agencies on Saturday, Sergei Aksenov declares that the armed forces, the police, the national security service and border guards will answer only to his orders. He says that any commanders who don't agree should leave their posts. (AP Photo/Darko Vojinovic)

Unidentified armed men patrol in front of Crimean parliament in Simferopol on March 1, 2014. Pro-Russian forces tightened their grip on Crimea on Saturday as the Kremlin vowed to help restore calm on the restive Ukrainian peninsula and Washington warned of "costs" to Moscow should it order in troops. AFP PHOTO/ GENYA SAVILOV

Young boys look on as unidentified armed individuals block the center of Balaklava, near Sevastopol, on March 1, 2014. Russia's parliament on March 1 gave President Vladimir Putin the go-ahead to send troops into Ukraine, despite a warning from Washington that such a deployment would results in "costs" for Moscow. The stark escalation of the ex-Soviet country's three-month political crisis came amid growing instability in Ukraine's predominantly Russian peninsula of Crimea that has housed Kremlin navies for nearly 250 years. AFP PHOTO/ VIKTOR DRACHEV

A woman walks her dogs past unidentified armed individuals blocking the center of Balaklava, near Sevastopol, on March 1, 2014. Russia's parliament on March 1 gave President Vladimir Putin the go-ahead to send troops into Ukraine, despite a warning from Washington that such a deployment would results in "costs" for Moscow. The stark escalation of the ex-Soviet country's three-month political crisis came amid growing instability in Ukraine's predominantly Russian peninsula of Crimea that has housed Kremlin navies for nearly 250 years. AFP PHOTO/ VIKTOR DRACHEV

Unidentified armed individuals block the base of the Ukrainian border guard service in Sevastopol, on March 1, 2014. Ukraine's border guard service said on March 1 that about 300 armed men were attempting to seize its main headquarters in the Crimean port city of Sevastopol under orders from Russian Defence Minister Sergei Shoigu. "The head of this group said that there are orders from the Russian defence minister to seize this naval post," Ukraine's border guard service said in a statement, adding that the men wore "full battle fatigues". AFP PHOTO/ VASILIY BATANOV

Unidentified armed individuals with armoured vehicles block the base of the Ukrainian border guard service in Sevastopol, on March 1, 2014. Ukraine's border guard service said on March 1 that about 300 armed men were attempting to seize its main headquarters in the Crimean port city of Sevastopol under orders from Russian Defence Minister Sergei Shoigu. "The head of this group said that there are orders from the Russian defence minister to seize this naval post," Ukraine's border guard service said in a statement, adding that the men wore "full battle fatigues". AFP PHOTO/ VASILIY BATANOV

An unidentified armed individual in an armoured vehicle blocks the base of the Ukrainian border guard service in Sevastopol, on March 1, 2014. Ukraine's border guard service said on March 1 that about 300 armed men were attempting to seize its main headquarters in the Crimean port city of Sevastopol under orders from Russian Defence Minister Sergei Shoigu. "The head of this group said that there are orders from the Russian defence minister to seize this naval post," Ukraine's border guard service said in a statement, adding that the men wore "full battle fatigues". AFP PHOTO/ VASILIY BATANOV

An unidentified armed individual in an armoured vehicle blocks the base of the Ukrainian border guard service in Sevastopol, on March 1, 2014. Ukraine's border guard service said on March 1 that about 300 armed men were attempting to seize its main headquarters in the Crimean port city of Sevastopol under orders from Russian Defence Minister Sergei Shoigu. "The head of this group said that there are orders from the Russian defence minister to seize this naval post," Ukraine's border guard service said in a statement, adding that the men wore "full battle fatigues". AFP PHOTO/ VASILIY BATANOV

An unidentified armed individual in an armoured vehicle blocks the base of the Ukrainian border guard service in Sevastopol, on March 1, 2014. Ukraine's border guard service said on March 1 that about 300 armed men were attempting to seize its main headquarters in the Crimean port city of Sevastopol under orders from Russian Defence Minister Sergei Shoigu. "The head of this group said that there are orders from the Russian defence minister to seize this naval post," Ukraine's border guard service said in a statement, adding that the men wore "full battle fatigues". AFP PHOTO/ VASILIY BATANOV

Unidentified armed individuals with armoured vehicles block the base of the Ukrainian border guard service in Sevastopol, on March 1, 2014. Ukraine's border guard service said on March 1 that about 300 armed men were attempting to seize its main headquarters in the Crimean port city of Sevastopol under orders from Russian Defence Minister Sergei Shoigu. "The head of this group said that there are orders from the Russian defence minister to seize this naval post," Ukraine's border guard service said in a statement, adding that the men wore "full battle fatigues". AFP PHOTO/ VASILIY BATANOV

Unidentified armed individuals with armoured vehicles block the base of the Ukrainian border guard service in Sevastopol, on March 1, 2014. Ukraine's border guard service said on March 1 that about 300 armed men were attempting to seize its main headquarters in the Crimean port city of Sevastopol under orders from Russian Defence Minister Sergei Shoigu. "The head of this group said that there are orders from the Russian defence minister to seize this naval post," Ukraine's border guard service said in a statement, adding that the men wore "full battle fatigues". AFP PHOTO/ VASILIY BATANOV

Unidentified armed individuals with armoured vehicles block the base of the Ukrainian border guard service in Sevastopol, on March 1, 2014. Ukraine's border guard service said on March 1 that about 300 armed men were attempting to seize its main headquarters in the Crimean port city of Sevastopol under orders from Russian Defence Minister Sergei Shoigu. "The head of this group said that there are orders from the Russian defence minister to seize this naval post," Ukraine's border guard service said in a statement, adding that the men wore "full battle fatigues". AFP PHOTO/ VASILIY BATANOV

Unidentified armed individuals with armoured vehicles block the base of the Ukrainian border guard service in Sevastopol, on March 1, 2014. Ukraine's border guard service said on March 1 that about 300 armed men were attempting to seize its main headquarters in the Crimean port city of Sevastopol under orders from Russian Defence Minister Sergei Shoigu. "The head of this group said that there are orders from the Russian defence minister to seize this naval post," Ukraine's border guard service said in a statement, adding that the men wore "full battle fatigues". AFP PHOTO/ VASILIY BATANOV

Unidentified armed individuals with armoured vehicles block the base of the Ukrainian border guard service in Sevastopol, on March 1, 2014. Ukraine's border guard service said on March 1 that about 300 armed men were attempting to seize its main headquarters in the Crimean port city of Sevastopol under orders from Russian Defence Minister Sergei Shoigu. "The head of this group said that there are orders from the Russian defence minister to seize this naval post," Ukraine's border guard service said in a statement, adding that the men wore "full battle fatigues". AFP PHOTO/ VASILIY BATANOV

People look at unidentified men in military fatigues blocking a base of the Ukrainian frontier guard unit in Balaklava on March 1, 2014. Ukraine's border guard service said that about 300 armed men were attempting to seize its main headquarters in the Crimean port city of Sevastopol under orders from Russian Defence Minister Sergei Shoigu. AFP PHOTO/ VIKTOR DRACHEV