WASHINGTON (AP) -- The Obama administration says Russia is sending attack helicopters to Syrian President Bashar Assad's regime and is warning about a dramatic escalation in the Arab country's 15-month conflict.

Secretary of State Hillary Rodham Clinton says the delivery represents the "latest information." She says the U.S. is concerned as the helicopters "will escalate the conflict quite dramatically."

She is calling instead for Moscow to help the U.S. push forward a political transition plan for Syria.

Clinton was speaking Tuesday at the Brookings Institution, a liberal-oriented research and policy organization.

Russia has consistently said it would not condone the use of outside forces to end the conflict and has said that it would not supply arms that would aid the government in quelling the uprising.