Shalqam is the first Libyan Foreign Minister to pay a formal visit to the US since 1972. Relations between the two countries have been improving over recent years, following the resumption of diplomatic relations in 2006 after a 27-year break.

In December, Rice said she would like to visit the country. This followed the visit by US Deputy Secretary of State John Negroponte to Tripoli in April last year, principally for talks on the Darfur crisis in Sudan.

Sean McCormack, a State Department spokesman, said the relationship was changing between Tripoli and Washington. “It is evolving. It is changing in a positive way,” he said. “There's still a lot to be done with respect to instituting basic freedoms within Libya.”

Shalqam and Rice were due to meet in Washington on 3 January. They were expected to discuss business links, human rights and democracy in Libya, as well as diplomatic issues in the wake of Libya assuming the rotating presidency of the UN Security Council on 1 January.

Shalqam was also expected to press for Libyan students to be given greater access to study at American universities.

"Bilateral relations between Libya and the United States are vital for us, for you, and for the region," Shalqam told the US-Arab Chamber of Commerce a day earlier. "We want American technology, knowledge and capital to return to Libya.”

Rice and Shalqam previously met in September 2006, on the sidelines of a UN General Assembly meeting in New York.

Libya became a non-permanent member of the UN Security Council on 1 January this year and has assumed the presidency for the month.