(USA TODAY) - The U.S. told an emergency meeting of the U.N. Security Council Thursday that Russia has "outright lied" over its military activity inside Ukraine, where Russian-backed separatists have been fighting the Ukrainian armed forces.
"Russian soldiers, tanks and air defense have supported and fight alongside separatists as they open a new front in a crisis manufactured and fueled by Russia," Samantha Power, U.S. ambassador to the U.N. told the council.
She noted that it was not the first time that Russia has been called to account by the council for its activities inside Ukraine.
"At every step, Russia has become before this council to say everything but the truth," Power said. "It has manipulated, obfuscated and outright lied."
The Security Council convened the emergency meeting only hours after Ukrainian President Petro Poroshenko declared that "Russian forces have entered Ukraine" in support of separatist rebels.
The meeting, called by Lithuania, also followed charges Thursday by NATO officials of a significant increase of Russian military activity -- including evidence of combat soldiers -- in eastern Ukraine. Russia has strongly denied such allegations.
"Russia has to stop lying and has to stop fueling this conflict," the U.S. ambassador said. "The mask is coming off. In these recent acts, we see Russia's actions for what they are -- a deliberate effort to support and now fight alongside illegal separatists in another sovereign country."
She said Russia's action in the past 48 hours "have spoken volumes" and called on the Security Council to take immediate action.
"How can we tell those countries that border Russia that their peace and sovereignty is guaranteed if we do not make our message heard on Ukraine," she asked the Council."The cost of inaction is unacceptable."
Jeffrey Feltman, U.N. undersecretary general for political affairs, opened the U.N. Security Council meeting by saying that its immediate focus "must be to find ways to reverse the dangerous escalation of fighting that has occurred over the past 24 hours and move quickly away from armed conflict and toward political solutions and dialogue."
Ukraine has charged that at least two convoys of Russian military equipment entered southeastern Ukraine this week to open up a third front in the fighting between Ukrainian armed forces and Russian-backed separatists in eastern regions.
More than 2,000 people have died in clashes in eastern Ukraine, according to a recent U.N. report. Russian-backed rebels have declared two regions as independent republics and the cities of Donetsk and Luhansk have been largely surrounded by Ukrainian forces.