Russian soldiers and pro-Russia volunteers reportedly took control of the Ukrainian Navy's headquarters in Sevastopol, Crimea, earlier today, in a (mostly) peaceful, but precarious power shift. 

AP/Andrew Lubimov

The BBC notes that some of those who stormed the base were armed, but that Ukrainian soldiers left the base willingly rather that stoke a fight: 

An officer inside the Sevastopol base told the BBC that some 200 pro-Russian activists had broken down the gates and gone inside, using an ambulance car. The senior Ukrainian officer at the scene was negotiating with them, he said. Later, there were reports that Ukrainian navy chief Serhiy Hayduk had been detained and taken away from the base by the Russian Federal Security Service (FSB). A number of Ukrainian servicemen were seen leaving the base. There have been no reports of clashes or shots being fired.

Other eyewitnesses, however, say that the group was unarmed. Navy captain Oleksander Balanyuk described the scene to Reuters, saying "this morning they stormed the compound. They cut the gates open, but I heard no shooting." CNN reported that closer to 300 pro-Russians stormed the headquarters, but also noted that none of them were carrying weapons.

Still, the ambush was frightening, according to Ukraine's navy fleet commander's assistant Marina Kanalyuk. "They are everywhere here," she told CNN, adding, "they surround us. They threaten us." And the message sent by Russia was pretty clear:

One Ukrainian serviceman was killed in Crimea yesterday, raising fears of more violence to come. Earlier that day, Russian President Vladimir Putin signed a draft bill annexing Crimea to Russia; an expected move. The international community has refused to recognize the land swap or the suspicious vote that approved the secession from Ukraine.

Today, Vice President Joe Biden issued yet another harsh warning to Russia, telling reporters that there are '"growing costs that come with naked aggression." Biden, currently in Lithuania as part of a Baltic tour, added that the U.S. takes its responsibility to aid NATO members "very, very seriously." Still, some wonder how effective Washington's condemnations are. Sanctions have not prevented Russia from appropriating Ukraine, and Putin doesn't show any sign of backing off plans to annex the region. 

According to CNN, the head of the Ukrainian government's press center said officials will attempt to visit Crimea today "to prevent the escalation of conflict."