Rice told a congressional panel that she had instructed the US charge d'affaires in Damascus, Michael Corbin, to meet with the Syrians as part of a new US initiative to tackle a growing Iraqi refugee crisis.

"We have a charge there who does have discussions with the Syrians about a variety of things," she said.

"But I have authorised him explicitly to talk to the Syrians about the issue of refugees."

Officials made clear this did not represent a break with standing US policy not to have high-level diplomatic dealings with the government of Syrian President Bashar al-Assad, which Washington accuses of backing anti-US extremists in Iraq, Lebanon and the Palestinian areas.

"This is consistent and in keeping with our existing relationship with Syria and not something that represents any kind of change in that approach," a senior State Department official said.

"Syria plays into it only to the extent that Syria is a prime location for Iraqi refugees," the official said. Between 600,000 and one million Iraqis are believed to be living in Syria.

The administration of President George W. Bush has been under pressure from domestic critics and overseas allies alike to enter into a dialogue with Syria and Iran as part of a broad diplomatic push to stabilize Iraq and further peace efforts in Lebanon and between Israelis and Palestinians.

But he and Rice have refused, arguing that the allied states would seek unacceptable concessions in exchange for their help.