crimea military
© UnknownSeparately, dozens of armed men in military uniforms without markings are patrolling the airport in Simferopol
Russian military forces are blocking an airport in the Black Sea port of Sevastopol in Crimea near the Russian naval base in an "armed invasion", Ukraine's interior minister has said.

Arsen Avakov said in a Facebook post that the Belbek international airport in Sevastopol is blocked by military units of the Russian navy. Mr Avakov described the blockade as a "military invasion and occupation."

Mr Avakov described the Sevastopol blockade as "an armed provocation" and said: "I consider what has happened to be a military invasion and occupation in violation of all international agreements and norms."

But Russia's Black Sea Fleet has denied its forces were involved in a seizure or blockade of the airport, according to the Interfax news agency.

"No units of the Black Sea fleet were deployed in the area of Belbek nor did they take place in blockading it," a statement from the fleet's press service said.

Separately, dozens of armed men in military uniforms without markings occupied Simferopol, the other main airport in Crimea in the early hours of this morning. A spokesman for the airport said it is operating as normal.

Ukraine's acting president has now called an emergency session of security chiefs to discuss the situation in Crimea. He proposed parliament hold a vote to adopt an appeal to Russia to "respect Ukraine's territorial integrity" and "reject support for separatism in Ukraine, of any form".

Relations between Russia and Ukraine have become increasingly strained following the ousting of president Viktor Yanokovych, particularly in Crimea, Ukraine's only region with an ethnic Russian majority.

Russian state television quoted eyewitnesses saying the men arrived at the Simferopol airport in the early hours.

It was not immediately clear who the men were, as they were wearing uniforms without any insignia.

One man told the BBC: "I'm with the People's Militia of Crimea. We're simple people, volunteers.

"We're here at the airport to maintain order. We'll meet the planes with a nice smile - the airport is working as normal."

On Thursday, masked gunmen with rocket-propelled grenades and sniper rifles seized the parliament and government offices in Simferopol and raised the Russian flag over the parliament building.

Ukraine's parliament elected a new government later that day, led by Olexander Turchynov, who promptly pledged to prevent any national division.

Russia also has granted shelter to Ukraine's fugitive president, Viktor Yanukovych, it emerged yesterday, who is wanted by the new government over the violence that led to the deaths of over 80 people during three days of bloody clashes.

Mr Yanukovych has a news conference scheduled this morning in Russia's south near the Ukrainian border. He has not been seen publicly since Saturday, and he declared Thursday in a statement that he remains Ukraine's legitimate president.

The escalating conflict has sent Ukraine's finances plummeting, prompting Western leaders to prepare an emergency financial package. The International Monetary Fund has said it is " ready to respond" to Ukraine's bid for financial assistance.

Ukraine's finance ministry has estimated it needs $35 billion (£21 billion) over the next two years to avoid default.

Ukraine's new prime minister, Arseniy Yatsenyuk, on Thursday said the country's future lies in the European Union, but with friendly relations with Russia.

Mr Yatsenyuk insisted the country wouldn't accept the secession of Crimea. The Black Sea territory, he declared, "has been and will be a part of Ukraine."

The events follow warnings from the interim president that any movements of Russia's troops from their Crimea naval base will be considered an act of "military aggression" yesterday, after it scrambled fighter jets to patrol borders in the first stirrings of a potentially dangerous confrontation reminiscent of Cold War brinksmanship.

The exercise came a day after US Secretary of State John Kerry warned Russian President Vladimir Putin to remember that the escalating crisis "is not Rocky IV".

Ukraine's population is divided in loyalties between Russia and the West. Crimea became part of Ukraine in 1954 when Soviet leader Nikita Khrushchev transferred jurisdiction from Russia.