The most senior American diplomat yet to visit the rebels in Libya is holding talks in their Benghazi strongold.
US Assistant Secretary of State Jeffrey Feltman has met the Transitional National Council, which rules the east of the country.
Colonel Muammar Gaddafi must leave power, the US reiterated in a statement released during the visit.
The Libyan rebels failed to gain full recognition when they travelled to Washington a week ago.
After those talks the US President Barack Obama went as far as to say the Transitional National Council (TNC) was a “legitimate and credible” interlocutor for the Libyan people, and he said it was inevitable that Col Gaddafi would leave power.