The U.S. said Russia "outright lied" about its military action in the Ukrainian conflict, while Russia again denied its involvement.

 "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., said  at an emergency Thursday meeting of the U.N. Security Council, USA Today reported.

 "At every step, Russia has come before this council to say everything but the truth," Power continued. "It has manipulated, obfuscated and outright lied."

NATO also released satellite footage of what it said were armed Russian troops inside eastern Ukraine. But Russian ambassador Vitaly Churkin downplayed the accusations, saying, "Everyone knows there are Russian volunteers in eastern Ukraine," he said according to USA Today.

"No one is hiding it," Churkin added before saying the insurgency that's been underway for the last five months is Ukraine's fault. Russian President Vladimir Putin has also blamed Ukraine for the uprising.

Instead of slamming Russia the U.S. should "restrain your geopolitical ambitions. Countries around the world would breathe a sigh of relief," Churkin said according to the newspaper.  

Hours before the emergency meeting, Ukrainian President Petro Poroshenko declared "Russian forces have entered Ukraine," prompting an emergency meeting with his own security council.

As officials argue over Russia's role in the conflict, fighting between Ukrainian forces and pro-Russian separatists raged on in eastern Ukraine. Shelling in the rebel stronghold city of Donetsk killed 11 people Wednesday night, USA Today reported.

Earlier Wednesday the southeastern city of Novoazovsk was completely overrun by rebel fighters. The city has seen three-days of nonstop shelling, according to the Associated Press.

An AP journalist tried to enter the town through a rebel checkpoint but was turned away. Another rebel said there was no fighting in the city.

Over 2,000 people have died since the insurgency began in April, according the U.N.