UN secretary general Ban Ki-Moon's envoy to Libya flew into Tunis on Monday, saying he would be joining talks between rebels and the government of embattled leader Muammar Gaddafi.
Former Jordanian foreign minister Abdul Ilah al-Khatib said negotiations on Libya's future would be taking place in a hotel in the Tunis suburbs.
Earlier, sources close to Tunisian security services said representatives of the two warring sides had met in Djerba, near the Tunisian-Libyan border. Libyan health minister Ahmed Hijazi and social affairs minister Ibrahim Cherif stayed in Djerba on Sunday, where they were joined by foreign minister Abdelati Obeidi, the national TAP news agency said.
Negotiations were under way with "several other foreign parties", the agency added, without giving details of the content of the talks.
A reliable source said an envoy of Venezuelan President Hugo Chavez, a Gaddafi ally, was also present.
Ban on Thursday reaffirmed "his strongly held belief that there can be no military solution to the Libyan crisis. "A ceasefire that is linked to a political process which would meet the aspirations of the Libyan people is the only viable means to achieving peace and security in Libya."
He urged Gaddafi and the rebels "to immediately engage" with Khatib, and "respond concretely and positively to the ideas presented to them, in order to end the bloodshed in the country."
Khatib has spent months shuttling between Tripoli and the rebel base at Benghazi trying to start ceasefire talks between the Gaddafi regime and the rebels' governing council.