BBC diplomatic correspondent
Syria says it has stopped military and intelligence co-operation with the US.
Syria says the US wants to topple Bashar al-Assad's regime
In an interview with the New York Times, Syria's ambassador to Washington said Damascus had severed all links with the US military and the CIA.
Imad Moustapha said Syria was reacting to American allegations that Syria was not doing enough to help stop the insurgency in neighbouring Iraq.
Relations between Damascus and Washington now seem to have reached a new low since the US invasion of Iraq.
This is the latest twist in their increasingly strained relations between Damascus and Washington.
The Syrians argue they have done all they can to co-operate with the CIA and Pentagon, but say the Bush administration is out to topple the regime in Damascus.
For its part Washington concedes Syria has been helpful in its fight against al-Qaeda, but far less so in its efforts to defeat the insurgency in neighbouring Iraq.
The Bush administration insists, with some justification, that the insurgency receives considerable funding and organisational support via Syria which must be stopped.
In the past, the administration has been split between those who feel Washington should work to improve co-operation with Damascus and those who argue that President Bashar Assad is another Baathist who simply needs to go.
With US Secretary of State Condoleezza Rice insisting last week that Syria was out of step with changes in the region, the hawkish view seems to be prevailing.
And though the US has not officially responded to Mr Moustapha's comments, administration sources say the options for dealing with the Syrian government include possible diplomatic, economic and even military action.