Kiev Says 2,000 Russian Troops in 'Armed Invasion' of Crimea, Asks Putin to Stop 'Aggression'

Russian aircraft carrying nearly 2,000 suspected troops have landed at a military air base near the regional capital of the restive Crimean peninsula, a top Ukrainian official said Friday, accusing Moscow of an "armed invasion."

"Thirteen Russian aircraft landed at the airport of Gvardeyskoye (near Simferopol) with 150 people in each one," Sergiy Kunitsyn, the Ukrainian president's special representative in Crimea, told the local ATR television channel, adding the air space had been closed.

It was not immediately clear if Russia had the right to use the base or send additional troops there under its agreements with Ukraine.

In the wake of the development, Ukraine's new interim president Oleksandr Turchynov asked Russian President Vladimir Putin to stop what he called the "naked aggression" against his country and to withdraw from the flashpoint Crimea peninsula.

"I personally appeal to President Putin to immediately stop military provocation and to withdraw from the Autonomous Republic of Crimea... It's a naked aggression against Ukraine," he told reporters.

Earlier on Friday, Ukraine accused Russia of staging an "armed invasion" of Crimea and appealed to the West to guarantee its territorial integrity after pro-Kremlin gunmen seized control of the peninsula's main airport.

Unidentified armed men in full combat gear were patrolling outside Crimea's main airport while gunmen were also reported to have seized another airfield on the southwest of the peninsula where ethnic Russians are a majority and where pro-Moscow sentiment runs high.

Ukraine's parliament immediately appealed to the U.S. and Britain to uphold a 1994 pact with Russia that guaranteed the country's sovereignty in return for it giving up its Soviet nuclear arms.

Both lawmakers and U.N. Security Council chair Lithuania said they would ask the world body to address the Crimea crisis at its next session -- a request that would need to gain support from veto-wielding members such as Russia.

Interim president Oleksandr Turchynov meanwhile attempted to regain control over unraveling security in the vast nation of 46 million by sacking the armed forces chief appointed by Yanukovych at the height of deadly protests last week.

Ukraine's general prosecutor also said Kiev would ask Moscow to extradite Yanukovych -- accused of mass murder over the protests -- if his presence is confirmed in Russia.

Western governments have been been watching with increasing alarm as Kiev's new pro-EU rulers grapple with dual threats of economic collapse and secession by Russian-speaking southern and eastern regions that had backed Yanukovych.

Putin this week stoked concerns that Moscow might use its military might to sway the outcome of Ukraine's three-month standoff by ordering snap combat drills near its border involving 150,000 troops and nearly 900 tanks.

U.S. Secretary of State John Kerry attempted to relieve diplomatic pressure in a crisis that has increasingly assumed Cold War overtones by announcing that Russian Foreign Minister Sergei Lavrov had assured him Moscow "will respect the territorial integrity of Ukraine".

Putin also appeared to take a more conciliatory approach Thursday by vowing to work on improving trade ties and promising to support international efforts to provide Kiev with funds that could keep it from declaring a debt default as early as next week.

But tensions were soaring by the hour in Russian-speaking Crimea -- a scenic Black Sea peninsula that has housed Kremlin navies for nearly 250 years and was handed to Ukraine as a symbolic gift by a Soviet leader in 1954.

Ukraine's Interior Minister Arsen Avakov accused Russian armed forces of being directly involved in dawn raids on an airport in Crimea's main city of Simferopol as well as an airfield.

Dozens of men in battle fatigues and armed with Kalashnikovs encircled the Simferopol airport and were checking all incoming and outgoing traffic although flights continued on schedule.

Unconfirmed reports by Ukrainian media said armed men had also seized the Belbek military air base near the city of Sevastopol -- home to Russia's Black Sea fleet.

AFP reporters saw soldiers with machineguns and dressed in green military fatigues that carried no national identification blocking the main road leading to the air base.

Avakov said the gunmen at Simferopol airport "are not even hiding the fact that they belong to the armed forces of the Russian Federation".

He also said Belbek was being blockaded by Russian navy military units.

"I consider what is happening to be an armed invasion and an occupation," Avakov said in a statement on his Facebook account.

The peninsula of nearly two million people has been in crisis since dozens of pro-Kremlin gunmen seized Crimea's parliament and government buildings Thursday and raised the Russian flag.

Crimean lawmakers appointed Russian Unity party member Sergiy Aksyonov as regional premier in place of a Kiev ally in a vote held late Thursday under the watchful eye of the militiamen.

Aksyonov said Friday he still recognized Yanukovych as Ukraine's legitimate head of state.

The fugitive leader has not been seen since making a brief taped television appearance that aired Saturday only hours before parliament stripped him of power in the wake of a week of carnage in Kiev that claimed nearly 100 lives.

Ukraine's bloodiest crisis since its 1991 independence erupted in November when Yanukovych made the shock decision to ditch an EU trade pact in favour of closer ties with old master Russia.

The 63-year-old announced from an undisclosed location on Thursday that he was "compelled to ask the Russian Federation to ensure (his) personal security."

Sources in his entourage said the ousted leader will appear before the media at 1300 GMT in Rostov-on-Don -- a Russian city less than two hours' drive from the Ukrainian border.

Meanwhile Switzerland said it was freezing the assets of 20 Ukrainian figures including Yanukovych and his multimillionaire son Olexandr and also launching a money laundering probe.

Austria also announced a similar move against 20 Ukrainian figures but did not identify them.

It is unclear whether Yanukovych himself has funds in Switzerland. But his 40-year-old son Olexandr opened a branch of his Management Assets Company (MAKO) in Geneva in late 2011.

Switzerland said it wanted to "avoid any risk of misappropriation of Ukrainian state assets".

Ukraine's new leaders are suffering from Moscow's decision to freeze a $15-billion bailout package Putin promised to Yanukovych in return for his rejection of the EU deal.

The central bank was forced Friday to lower the maximum amount of money individuals can withdraw from banks in a day to about 1,100 euros ($1,400) from a 4,000-euro ($5,500) limit imposed on February 7.

The hryvnia had plunged about 13 percent between Wednesday and Thursday before regaining some strength on Friday amid expectations of the imminent delivery of urgent Western aid.