SIMFEROPOL, Ukraine — The Kremlin power play in Ukraine's strategic Crimea region escalated Sunday with Russian-backed authorities ordering Ukrainian army and navy units to surrender their weapons as an outraged international community warned Russian President Vladimir Putin that he risks censure for violating Ukraine's sovereignty.
The United States accused Moscow of reinforcing an estimated 6,000 ground and naval troops in Crimea with additional personnel and announced that Secretary of State John F. Kerry would fly to Kiev, Ukraine's capital, on Tuesday in a show of support for the beleaguered Ukrainian government.
The demand that Ukrainian troops surrender, read on television by the new head of Crimea's regional government, appeared to be aimed at consolidating Russia's hold on the peninsula, which is home to the Black Sea fleet and the largest ethnic Russian community in this former Soviet republic.
There was little evidence that Ukrainian military forces, whose bases have been blocked off by Russian troops, were heeding the order to give up their weapons and abandon their posts.
However, the cohesion and loyalty of Ukraine's armed forces were called into doubt when the commander of the navy defected to the side of Crimea's new premier, Sergei Aksenov.
Adm. Denis Berezovsky announced that he had sworn allegiance to the Crimean government leader installed Thursday by pro-Moscow lawmakers, who met under guard by masked and heavily armed Russian soldiers.
Ukrainian acting President Oleksandr Turchynov said Berezovsky was being charged with treason.
Both Aksenov and leaders in the embattled new government in Kiev mobilized reservists to bolster their armed forces a day after Putin received parliamentary approval to send Moscow's armed forces into Ukraine, which gained independence in 1991. Putin said the deployment was needed to protect ethnic Russians and Kremlin military installations from what Russia portrays as grave danger in the wake of last month's ouster of Ukraine's pro-Russia president, Viktor Yanukovich.
Hundreds of armed Russians, many of them retired or inactive veterans of the Black Sea fleet, surrounded Ukrainian military installations in Crimea. They sported black-and-orange ribbons signifying the Soviet victory in World War II or red armbands identifying themselves as "volunteers of the autonomous republic of Crimea."
The motley reserves joined thousands of professional Russian troops activated by Moscow in Crimea over the last three days in a defiant challenge to a Kiev government portrayed by Russian media and politicians as neofascist bandits and radicals.
There were no reports of armed confrontation, but Western leaders alarmed by the standoff have warned that the atmosphere of hostility and mistrust could spark bloodshed even if neither side intends it.
In Washington, senior administration officials said in a conference call with reporters that the Russian military was "settling in" and strengthening its hold on Crimea. They confirmed that additional forces flown into Crimea on Sunday had surrounded Ukraine's small contingent of troops in the region.
In Kiev, acting Prime Minister Arseny Yatsenyuk called the Russian troop movements and call to arms of Crimea's ethnic Russian population "a declaration of war."
After a closed session of parliament, Yatsenyuk said Ukraine was "on the brink of national disaster" and urged Putin to pull back Russian forces to their bases, saying the Kremlin leader surely didn't want to be "the president who starts war between two friendly and neighboring countries" but was inches away from doing so.
Ukrainian reservists were activated Sunday to bolster regular armed forces that even Kiev's interim defense minister, Ihor Tenyuh, has acknowledged are outnumbered and outflanked by Russia's forces.
Turchynov said his efforts to reach Kremlin officials were rebuffed.
U.S. and other Western officials have put Moscow on notice that it risks expulsion from the community of democratic nations if it persists in interfering in Ukraine's political crisis.
Kerry, denouncing what he called Russia's invasion of Ukraine as an "incredible act of aggression," said the United States was considering economic sanctions to persuade Putin to change course or to punish him if he refuses.
Moscow's decision to send troops to Crimea "is really a stunning, willful choice by President Putin to invade another country," said Kerry, speaking on CBS' "Face the Nation."
Yuri Sergeyev, Ukraine's ambassador to the United Nations, said on CNN's "State of the Union" that Ukrainians are "preparing to defend ourselves" and called for military backing from the West. "When the Russian troops … are enlarging their quantity with every coming hour, naturally we will ask for military support and other kinds of support."
In Brussels, NATO Secretary-General Anders Fogh Rasmussen said Russia had violated the U.N. charter with its military action in Ukraine. The North Atlantic Treaty Organization isn't obliged to defend Ukraine, which is not a member, but Kiev has taken part in NATO military exercises, and the country's new leaders are known to want eventual membership in the Western military alliance — a prospect that has unsettled Russia.
Hostilities in Ukraine flared to a deadly crescendo two weeks ago, when a 3-month-old rebellion against Yanukovich culminated with more than 80 demonstrators and police being killed in a bloody three-day battle. The protest movement that came to be known as the Maidan was sparked by Yanukovich's late-November decision to scrap an association agreement with the European Union in favor of maintaining Ukraine's close economic integration with Russia.
Crimea's new leadership doesn't recognize Kiev's authority and will hold a referendum March 30 to gauge the region's preference for remaining within Ukraine or seceding and aligning with Russia, said Crimean parliament speaker Vladimir Konstantinov. Ethnic Russians and Russian speakers make up just 17% of Ukraine's population but are a majority in Crimea.
Most of those gathered around Simferopol's government buildings Sunday were celebrating the Russian takeover, but not all were in favor of the Kremlin's intrusive hand.
"We don't need invaders in our streets," said Ruslan Kavpak, 42, an ethnic Russian engineer. "We haven't invited them. There is no violence here. By deploying Russian soldiers in the Crimea, they sow mutual suspicion and set people of different nationalities against one another."