US Secretary of State Hillary Clinton is in Libya on an unannounced visit aimed at showing support for the Libyan people and building ties. Mrs Clinton is expected to be in the capital, Tripoli, for only a few hours. She is the first US cabinet-level official to visit the country. Her visit was kept secret due safety concerns and heavy security measures were in place ahead of her arrival. Her trip follows visits to Libya by the British and French leaders. Mrs Clinton will holds talks with top officials from the Libyan National Transitional Council (NTC) - Chairman Mustafa Abdul Jalil, Prime Minister Mahmoud Jibril and Finance Minister Ali Tarhouni. She will also hold a town hall meeting with women, young people and civil society leaders. US officials say the visit is meant to show support for the NTC and the Libyan people, but also to start building a solid relationship with Libya. Earlier on Tuesday there were reports of fierce fighting around the city of Sirte, Col Gaddafi's hometown and where loyalists are still resisting forces loyal to the NTC. About 1,000 Libyan fighters launched a major assault from the east of the city, the Associated Press reported. Malta visit Mrs Clinton flew in to Tripoli from Malta. There she met Maltese Prime Minister Lawrence Gonzi to discuss the situation in Libya and thank the Maltese authorities for their assistance during the crisis in the north African country. The island has been a centre for humanitarian aid efforts and the evacuation of workers from Libya. Mrs Clinton is the most senior US administration official to visit the island since President George Bush Sr and Secretary of State James Baker came in 1989 for a summit with then-Soviet President Mikhail Gorbachev.