Russian parliament has confirmed President Vladimir Putin Saturday request for permission to use the country's military in Ukraine, moving to formalize troop deployments that Ukrainian officials have described as an ongoing invasion of the strategic region of Crimea.
In response, Vitaly Klitschko, a senior Ukrainian politician and likely presidential candidate, called on Saturday for a "general mobilisation" following Russian parliament's decision to approve deploying troops in Ukraine's Crimea region.
At the request of Britain, the UN Security Council will hold an urgent meeting on the crisis in Ukraine on Saturday. EU foreign ministers will also hold an emergency meeting in Brussels on Monday to discuss the situation.
Putin's call came as pro-Russian demonstrations broke out in major cities in eastern and southern Ukraine, where protesters raised Russian flags and beat up supporters of the new Ukrainian government.
The Federation Council (the upper house) voted overwhelmingly to back a proposal to use "the armed forces of the Russian Federation on the territory of Ukraine until the normalisation of the socio-political situation in that country."
It was the latest escalation following the ouster of Ukraine's pro-Russian president last week by a protest movement aimed at turning Ukraine toward the European Union and away from Russia.
- Russian troop movements in Crimea may destabilize Ukraine
- Obama to Russia: There will be 'costs' for Ukraine intervention
- Armed men seize two airports in Ukraine's Crimea
Putin's motion loosely referred to the "territory of Ukraine" rather than specifically to Crimea, raising the possibility that Moscow could use military force in other Russian-speaking areas in eastern and southern Ukraine where many oppose the new authorities in Kiev.
He said the move is needed to protect ethnic Russians and the personnel of a Russian military base in Ukraine's strategic region of Crimea. Putin sent the request to the Russian legislature's upper house, which has to approve the motion, according to the constitution.
Putin's statement, and remarks from a pro-Russian leader installed in Crimea this week, effectively confirmed what most people in the region had assumed: that military units who had seized control in the past two days were indeed Moscow's.
Ukraine accused Russia of sending thousands of extra troops to Crimea, largely hostile to the Kiev government which emerged from the overthrow of president Viktor Yanukovich last weekend. It placed its military in the area on high alert.
President Barack Obama warned Moscow on Friday "there will be costs" if Russia intervenes militarily.
In Crimea, the pro-Russian regional prime minister had earlier claimed control of the military and police there and asked Putin for help in keeping peace, sharpening the discord between the two neighboring Slavic countries.
Armed men described as Russian troops took control of key airports and a communications center in Crimea on Friday. Ukraine has accused Russia of a "military invasion and occupation" -- a claim that brought an alarming new dimension to the crisis, and raised fears that Moscow is moving to intervene on the strategic peninsula where Russia's Black Sea fleet is based.
Ukraine's population is divided in loyalties between Russia and Europe, with much of western Ukraine advocating closer ties with the European Union while eastern and southern regions look to Russia for support. Crimea is mainly Russian-speaking.
Crimean's prime minister, Sergei Aksyonov, declared that the armed forces, the police, the national security service and border guards in the region will answer only to his orders.
'Recall your forces'
Ukrainian Prime Minister Arseny Yatsenyuk opened a Cabinet meeting in the capital, Kiev, by calling on Russia not to provoke discord in Crimea, a peninsula on the Black Sea.
"We call on the government and authorities of Russia to recall their forces, and to return them to their stations," Yatsenyuk was quoted as saying by the Interfax news agency. "Russian partners, stop provoking civil and military resistance in Ukraine."
Russia put pressure on Ukraine from another direction when a spokesman for state gas company Gazprom said that Ukraine owed $1.59 billion in overdue bills for imported gas. Sergei Kuprianov was quoted by the RIA-Novosti agency as saying the gas arrears would endanger a recent discount granted by Russia. The discount lowered the price to $268.50 per thousand from other $400. The Russian payment demand and loss of the discount would accelerate Ukraine's financial crisis. The county is almost broke and seeking emergency credit from the International Monetary Fund.
Crimea only became part of Ukraine in 1954 when Soviet leader Nikita Khrushchev transferred jurisdiction from Russia, a move that was a mere formality when both Ukraine and Russia were part of the Soviet Union. The Soviet breakup in 1991 meant Crimea landed in an independent Ukraine.
Russia has taken a confrontational stance toward its southern neighbor after pro-Russian President Viktor Yanukovych fled the country. Yanukovych was voted out of office by parliament after weeks of protests ended in violence that left over 80 people dead.
Demonstrators sought his resignation after he backed out of signing an agreement to bring Ukraine closer to the European Union instead of Russia. Yanukovych took refuge in Russia and still says he's president.
Aksyonov, the head of the main pro-Russia party on the peninsula, appealed to Putin "for assistance in guaranteeing peace and calmness on the territory of the autonomous republic of Crimea." Aksyonov was voted in by the Crimean parliament on Thursday after pro-Russia gunmen seized the building and as tensions soared over Crimea's resistance to the new authorities in Kiev, who took office this week.
Obama called on Russia to respect the independence and territory of Ukraine and not try to take advantage of its neighbor, which is undergoing political upheaval.
He said such action by Russia would represent a "profound interference" in matters he said must be decided by the Ukrainian people.
"The United States will stand with the international community in affirming that there will be costs for any military intervention in Ukraine," he said. He did not say what those costs might be.
Swedish Foreign Minister Carl Bildt wrote on Twitter that it was "obvious that there is Russian military intervention in Ukraine. Likely immediate aim is to set up puppet pro-Russian semi-state in Crimea."
At the United Nations, the Ukrainian ambassador, Yuriy Sergeyev, said Friday that Russian transport aircraft and 11 attack helicopters had arrived in Crimea illegally, and that Russian troops had taken control of two airports in Crimea.
He described the gunmen posted outside the two airports as Russian armed forces as well as "unspecified" units.
Russia has kept silent on claims of military intervention and has said any troop movements are within agreed rules, even as it maintained its hard-line stance on protecting ethnic Russians in Crimea.
Meanwhile, flights remained halted from Simferopol's airport. Dozens of armed men in military uniforms without markings patrolled the area. They didn't stop or search people leaving or entering the airport, and refused to talk to journalists.
The Associated Press contributed to this report