The new Ukrainian government said Friday it had been invaded by Russia and appealed for the United States and United Kingdom to protect it, as guaranteed under a 1994 agreement.

The move came after a series of armed takeovers and provocations in the Crimea region that began on Thursday with the seizure of the regional parliament building and continued on Friday:

Armed groups took over access to both main airports on the Crimean Peninsula.

The Ukrainian border guard service claimed that more than 10 Russian military helicopters flew from Russia into Ukrainian airspace over the Crimea region. It also said eight Russian transport planes had landed in Crimea with unknown cargo.

Russia confirmed that armoured vehicles attached to its naval base were moving around Crimea for “security” reasons.

Uniformed Russian servicemen were blocking off a unit of Ukrainian border guards in the port city of Sevastopol, where part of the Russian Black Sea fleet is based, according to Ukraine’s border service.

Ukrainian International, Ukraine’s biggest airline, said the airspace over the Crimea region had been closed.

The U.N. Security Council will hold private consultations to discuss the crisis in Ukraine on Friday afternoon, a U.N spokesman said. Russian President Vladimir Putin discussed the situation in separate phone calls with European Council President Herman Van Rompuy, German Chancellor Angela Merkel and British Prime Minister David Cameron.

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In Canada, Prime Minister Stephen Harper pledged Canada's unwavering support for Ukraine's territorial integrity in the face of "worrying" developments in the former Soviet state, even as Foreign Minister John Baird met with the new leadership in Kiev.

In Washington, President Barack Obama expressed concern about reported Russian military movement inside crisis-torn Ukraine and warned of consequences.

"Any violation of Ukraine's sovereignty and territorial integrity would be deeply destabilizing," he said in a brief appearance. "The United States will stand with the international community in affirming that there will be costs for any military intervention in Ukraine."

Crimea, a Russian-speaking region that has rejected the overthrow of the Moscow-backed Viktor Yanukovych and the rise to power of pro-Western forces in Kiev.

In Kiev, Ukraine's parliament adopted a resolution on Friday demanding that Russia halt steps it says are aimed against Ukraine's sovereignty and territorial integrity. The parliament also called for guarantees of the memorandum signed by Ukraine, Britain, Russia and the United States in Budapest in 1994. That agreement guaranteed Ukraine's sovereignty and current borders in exchange for surrendering the nuclear weapons that were left after the collapse of the Soviet Union.

It wasn't clear whether the gunmen who seized the airports were Russian soldiers or pro-Russian militiamen. They wore no insignia, but carried automatic weapons and Russian flags into the airport.

On the road north of Sevastopol, which hosts Russia's Black Sea Fleet, The Globe and Mail saw 12 military trucks with soldiers in the back. None had licence plates.

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The road to Sevastopol's Belbek airport was blocked by another military truck and at least seven armed men. A local member of "Russkiy Bloc" a pro-Russian political party that has organized "self-defence" units, said he didn't know who the men blocking the airport road were.

"I was in the army for 10 years, and I can't say whether these are professional soldiers," said 42-year-old Andrei Sitnikov. "All I can say is they are people with guns."

In a posting on his Facebook page, Ukraine's new Interior Minister, Arsen Avakov, called the airport takeovers an "ARMED INVASION and OCCUPATION" by the "armed forces of the Russian Federation."

"It is a direct provocation of armed bloodshed in the territory of a sovereign State," Mr. Avakov wrote. "It is not the competence of the Ministry of internal affairs. This is the competence of the NATIONAL SECURITY and DEFENSE COUNCIL."

Russia's Interfax news agency had reported earlier that "Russian servicemen" had gone to Belbek military airport to prevent "fighters" from flying in.

With gunmen in the building and the Russian flag flying from the roof, deputies in Crimea's regional legislature appointed a new government and passed a motion Thursday calling for a referendum on the future as part of Ukraine.

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Raising the possibility of Taiwan-and-China-style duelling governments in Ukraine, the newly appointed head of the Crimean administration has pledged allegiance to Mr. Yanukovych.

Crimea's move toward autonomy – or some kind of association with Russia – was accompanied by fresh sabre-rattling from Kremlin, which put fighter jets on alert a day after announcing snap military drills along its border with Ukraine. And, in his first statement in almost a week, the deposed Mr. Yanukovych said he had taken refuge in Russia from "extremists" in Ukraine who had threatened him with bodily harm.

Moscow has denounced the fall of Mr. Yanukovych and the rise of pro-Western forces in Kiev as an armed coup, and has refused to recognize the new government. Crimea was part of Russia for two centuries before Nikita Khrushechev transferred it to Soviet Ukraine in 1954.

"I am addressing the Russian Black Sea Fleet command with a demand: all military servicemen should stay within the boundaries of the territories stipulated by the agreement," Ukraine's Interim President Oleksandr Turchynov said Thursday. "Any movement of military servicemen with weapons outside this territory will be viewed as military aggression."

The gunmen who seized control of Crimea's regional parliament were widely believed to be members of Berkut, a riot police force that was disbanded this week by the new government in Kiev, which blamed the force for much of the bloodshed in Kiev. Serhiy Kunitsyn, a former Crimean premier who is now an opposition MP in Kiev, told the national parliament that 120 people who were involved in the takeover of the Crimean government buildings.

"These professionally trained people are armed. They brought weapons - automatic weapons, grenade launchers, and machine guns," Mr. Kunitsyn said.

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With reports from Adrian Morrow, Associated Press and Reuters