US Secretary of State Hillary Clinton has warned Russia that its stance over the crisis in Syria puts its Middle East interests "at risk".
Clinton urged the Russians to "move more constructively" and back UN envoy Kofi Annan's peace plan.
The United States and Russia are embroiled in a furious diplomatic row after both sides accused each other of supplying arms to Syria.
The US Secretary of State has accused Russia of escalating the conflict in Syria and lying about their involvement in the country.
Foreign Secretary William Hague has told MPs in the House of Commons that Syria is "on the edge of civil war."