Thousands of Syrians have taken to the streets in an anti-US demonstration organised by the government in the capital Damascus.
They were protesting against a US air raid in the east of the country on Sunday which killed at least eight civilians. According to US officials, a man who helped smuggle foreign fighters into Iraq was among them.
Damascus has condemned the raid calling it a “terrorist attack”.
The raid has further undermined strained ties between the US and Syria, whom Washington accuses of letting through foreign fighters into Iraq.
Syrian authorities have reacted by closing an American school and a cultural centre in the capital. Washington has temporarily shut down its embassy.
The crisis comes as Iraq tries to negotiate an amendment to a draft document which sets the conditions for US troops to operate in the country after their UN mandate expires in December.
Iraq wants to ban US forces from striking neighbouring countries using its territory as a launchpad.
Under the deal, US troops would have to withdraw completely from Iraq by the end of 2011.