BENGHAZI, Libya — Libya’s rebels will agree to a cease-fire if Moammar Gadhafi pulls his forces out of cities and allows peaceful protests against his regime, an opposition leader said today.

Mustafa Abdul-Jalil, head of the opposition’s interim governing council based in Benghazi, spoke during a joint press conference with U.N. envoy Abdelilah Al-Khatib. Al-Khatib is visiting the rebels’ de facto stronghold of Benghazi in hopes of reaching a political solution to the crisis.

Abdul-Jalil said the rebels’ condition for a cease-fire is “that the Gadhafi brigades and forces withdraw from inside and outside Libyan cities.”

The U.N. resolution that authorized international airstrikes against Libya called for Gadhafi and the rebels to end hostilities. Gadhafi announced a cease-fire immediately but has shown no sign of heeding it. His forces continue to attack rebels in the east, where the opposition is strongest, and have besieged the only major rebel-held city in the west, Misrata.

Abdul-Jalil said the regime must withdraw its forces and lift all sieges.

He stressed the ultimate goal was Gadhafi’s ouster.

The U.N. said Al-Khatib, arrived Thursday in Tripoli.

Forces loyal to Libya’s leader of nearly 42 years spent much of this week pushing the rebels back about 100 miles along the coast, and the opposition was trying to regroup.

The rebels had mortars today, weapons they previously appeared to have lacked, and on Thursday night they drove in a convoy with at least eight rocket launchers — more artillery than usual.

The rebels also appeared to have more communication equipment such as radios and satellite phones, and were working in more organized units, in which military defectors were each leading six or seven volunteers.

The rebels’ losses this week, and others before airstrikes began March 19, underlined that their equipment, training and organization were far inferior to those of Gadhafi’s forces.