U.S. Permanent Representative to the United Nations Samantha Power has said she believes that Russia, through its influence on separatists in Ukraine, may put an end to the armed conflict in eastern Ukraine.

She said at a UN Security Council meeting on Monday that Russia continued to support separatists, providing them with weapons and not urging them to lay down their arms.

Power noted that separatists controlling the Malaysian plane crash site in eastern Ukraine were obstructing the investigation into the plane tragedy in Ukraine.

"We condemn the actions of the separatists who control the site. Indeed, almost everyone has condemned this grotesque behavior," she said.

Power said she was troubled by the fact that Russian officials had blamed Ukraine for the plane crash, while knowing that a missile was launched by pro-Russian separatists.

"For the past six months, Russia has seized Ukrainian territory and ignored the repeated requests of the international community to de-escalate – all in an effort to preserve influence in Ukraine, a country that has long made clear its desire to maintain constructive ties with Moscow," she said.

Power said that Russia may make separatists agree to a truce with the Ukrainian authorities and lay down their arms.

"It would constitute a long overdue sign that Russia is willing to take steps to end this deadly crisis," she said.