Assistant Secretary of State Ellen Sauerbrey will travel to Damascus "in coming weeks" as part of a regional tour dealing with "humanitarian issues related to Iraqi refugees," said State Department spokesman Sean McCormack.

Playing down the diplomatic significance of the trip, McCormack said Sauerbrey would be "paired" on the tour with a representative of the UN High Commissioner for Refugees (UNHCR). "It's not a bilateral mission," he said.

But he said Sauerbrey, who handles refugee and migration affairs at the State Department, would be authorised to meet with her Syrian counterparts to discuss the refugee issue.

She will also visit Jordan and possibly other countries in the region, he said.

Sauerbrey will be the highest-ranking US official to visit Syria since early 2005, when then-deputy secretary of state Richard Armitage travelled to Damascus.

The United States withdrew its ambassador from Damascus after Syrian authorities were implicated in the February 2005 assassination in Beirut of former Lebanese prime minister Rafiq Hariri.

Under President George W Bush, the United States has since refused high-level contacts with Syria, which it accuses of backing anti-US insurgents in neighbouring Iraq and supporting efforts by the Lebanese Islamic movement Hezbollah to topple the pro-Western government of Lebanon.