He told The Associated Press that the Il-76 planes arrived unexpectedly and were given permission to land, one after the other, at Gvardeiskoye air base, north of the regional capital, Simferopol. Astakhov said the people in the planes refused to identify themselves and waved off customs officials, saying they didn't require their services.
Russia kept silent on claims of military intervention, even as it maintained its hard-line stance on protecting ethnic Russians in Crimea, a territory that has played a symbolic role in its national identity.
Ukraine's U.N. ambassador said Friday that he told the U.N. Security Council that Russian military helicopters and transport planes are entering his country and that Russian armed forces seized Crimea's main airport.
Associated Press journalists in Crimea spotted a convoy of nine Russian armored personnel carriers on a road between the port city of Sevastopol, where Russia has a naval base, and the regional capital, Simferopol. The tensions at two Crimea airports apparently caused the closure of airspace over the peninsula.
Russia's Interfax agency cited Serhyi Kunitsyn, a Ukraine presidential envoy to Crimea, telling ATR television that 13 Russian planes carrying 150 Russian troops each landed at Gvardeiskoye air base. That report could not be confirmed.
In Washington, Obama said the U.S. is deeply concerned by reports of military movements by Russia inside Ukraine. He said any violation of Ukraine's sovereignty and territorial integrity would be destabilizing.
He also said it would violate Russia's commitment to respect Ukraine's borders and would invite global condemnation. Obama said the United States stands with the world community to affirm there will be costs for an intervention.
Russian armored vehicles bearing the nation's tricolor rumbled across Crimea and men described as Russian troops took position at airports and a coast guard base.
The sudden arrival of men in military uniform patrolling key strategic facilities prompted Ukraine to accuse Russia of "military invasion and occupation" — a claim that brought an alarming new dimension to the crisis.
Oleksandr Turchynov, who stepped in as president after Viktor Yanukovych fled Kiev last weekend, urged Russian President Vladimir Putin to stop "provocations" in Crimea and pull back military forces from the peninsula. Turchynov said the Ukrainian military would fulfill its duty but would not be drawn into provocations.
Earlier Friday Ukraine's fugitive president resurfaced in Russia to deliver a defiant condemnation of a "bandit coup."
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