British Foreign Secretary William Hague has held talks with Libya's alternative government, the National Transitional Council, in the rebel city of Benghazi.
Mr Hague said on Friday that the visit was designed to show support for the legitimate representatives of the Libyan people.
The Gaddafi government has ''strongly denounced'' what it called the ''illegal'' visit.
A statement on the Jana state news agency said Mr Hague's visit was an interference with the internal affairs of a sovereign nation.
Mr Hague reiterated his call for Colonel Gaddafi to go.
''Of course we all want a political not a military solution I think to any conflict, including this one. But that is only possible if Colonel Gaddafi will go,'' he said.
'''You only have to talk to the people here, see the graffiti that is written on all the walls, listen to anybody in the street, to realise that there isn't a political solution that involves Gaddafi still being at the head of Libya.''
The BBC reports Mr Hague and International Development Secretary Andrew Mitchell also visited a medical centre, met citizens of Benghazi and laid a wreath at Commonwealth war graves.
Mr Mitchell announced new UK support for the clearance of mines in Misrata, Benghazi and other affected areas to help ensure the safety of 200,000 people.