The United States signalled Wednesday that it was seeking possible UN action against Syria for Damascus' alleged interference in Lebanon and aid to insurgents in Iraq.
"There are discussions about what is the appropriate mechanism to address Syrian behaviour within the UN context," said a senior State Department official who asked not to be named.
Secretary of State Condoleezza Rice told the Senate Foreign Relations Committee that Washington was taking "new diplomatic steps" to stop assistance to Iraqi insurgents from Syria and Iran.
US officials did not specify what actions the administration of President George W. Bush envisioned against Damascus.
But the Washington Post reported Wednesday that the United States and France were planning to propose two resolutions at the UN Security Council next week to hold Syria accountable for meddling in Lebanon.
Rice said in Senate testimony that the United States had taken military action to close off the Syria-Iraq border and "we have also begun taking new diplomatic steps to convey the seriousness of our concerns."
"Syria and Iran allow fighters and military assistance to reach insurgents in Iraq," she said.
Rice said, "Syria and Iran must decide whether they wish to side with the cause of war or with the cause of peace."