Rebels in Libya's western mountains say they have advanced and are battling leader Moammar Gadhafi's forces in a strategic town 80 kilometers southwest of the capital, Tripoli.
Opposition commanders said Sunday's fighting on the outskirts of Bair al-Ghanam follows weeks of intense clashes in the Nafusa Mountains that have pushed government troops steadily back toward the capital.
The town is significant because it is only 30 kilometers from Zawiya, a key western gateway to Tripoli and home to a crucial oil refinery. Opposition forces seized Zawiya in March before pro-Gadhafi fighters retook the city.
A ship carrying 106 Libyans arrived in Tripoli early Sunday from the eastern rebel stronghold of Benghazi. The ferry was organized by the International Committee of the Red Cross, which transported about 300 people to Benghazi from Tripoli on Friday.
Meanwhile, African Union leaders meeting in Pretoria said Mr. Gadhafi has agreed to stay out of negotiations to end Libya's more than four-month-old civil war. The AU said in a statement Sunday that it "welcomes Mr. Gadhafi's acceptance of not being part of the negotiation process."
There was no immediate confirmation from the Libyan government of what could be a significant concession.
Late Sunday, Mr. Gadhafi's spokesman remained defiant, insisting the Libyan leader "is leading the country. He will not leave. He will not step down." Mr. Gadhafi has run Libya for 42 years, but is being pressured to cede power by rebels who rose up against his rule and by a NATO-led bombing campaign.
In Pretoria, South African President Jacob Zuma warned NATO not to use its military power to kill Mr. Gadhafi. Mr. Zuma said the U.N. resolution authorizing allied action in Libya is designed to protect the Libyan people, not to pursue "regime change or political assassination."
NATO has denied targeting Mr. Gadhafi after a May 1 airstrike that Libya's government said killed four members of the Gadhafi family. Russia at the time expressed doubts about NATO's denial.
Judges at the International Criminal Court are expected to convene Monday in The Hague to hand down war crimes indictments against Mr. Gadhafi and two of his most trusted lieutenants.
ICC Prosecutor Luis Moreno-Ocampo has asked for arrest warrants for Mr. Gadhafi, his son Seif al-Islam and the head of Libyan intelligence, Abdullah al-Senussi.