US Secretary of State Hillary Clinton flew in to Tripoli on Tuesday on a previously unannounced visit as Libya's new rulers try to crush the last pockets of resistance by pro-Moamer Kadhafi fighters.

The first US cabinet official to visit Libya since 2008, when Washington wanted to forge a new relationship with Kadhafi, Clinton is seeking to bolster ties with the new rulers and promote Libya's transition to democracy.

In a lightning visit amid tight security, the chief US diplomat was to meet National Transition Council (NTC) chairman Mustafa Abdel Jalil, interim prime minister Mahmud Jibril as well as Ali Tarhuni, the oil and finance minister.

Her visit to this oil-rich country follows those by French President Nicolas Sarkozy, British Prime Minister David Cameron, Turkish Prime Minister Recep Tayyip Erdogan as well as foreign ministers from Britain, Italy, and Canada.

Speaking on the flight from Washington to Tripoli, via Malta, a senior US State Department official said the United States aims to forge new civilian ties with the Libyan people as the US-backed NATO air mission winds down.