Western media reports say Libyan rebels battled for towns on both sides of Tripoli Saturday, tightening a siege around Libyan leader Moammar Gadhafi's stronghold in the capital.
The reports said rebels took control of the city of Zawiya, only 50 kilometers west of Tripoli, and were occupying positions formerly held by pro-Gadhafi forces, who continued shelling the city from the east.
In another apparent victory for the rebels, a senior rebel commander said Saturday his fighters were in full control of the eastern town of Brega after seizing its industrial sector, which also contains a major oil refinery. The claim could not be verified independently.
Fighting spilled across the border into Tunisia, where clashes erupted overnight between Tunisian troops and a group of Libyans traveling in vehicles with weapons. Tunisian forces reported several casualties, but did not say whether the fighters were Libyan rebels or pro-Gadhafi soldiers.
A Tunisian helicopter, meanwhile, crashed early Saturday in the border area, killing the pilot and co-pilot. The cause of the crash was under investigation.
Mr. Gadhafi has seen the areas under his control shrink significantly in recent weeks as rebels advance on Tripoli from the west, east and south after six months of fighting to end his four-decade autocratic rule.
NATO warplanes have been supporting the rebels by bombing pro-Gadhafi forces to enforce a U.N. Security Council resolution authorizing military action to protect Libyan civilians from government attacks.
In other developments, two more Gadhafi aides appear to have defected to the rebel side. Tunisian officials say the Libyan leader's former number-two, Abdel-Salam Jalloud, departed from the Tunisian island of Djerba on a flight to Italy Saturday. A day earlier, Libyan rebels said Jalloud, a former prime minister, had joined their ranks.
Tunisian officials also said Libyan Oil Minister Omran Abukraa has decided not to return to Libya after a recent mission to Italy. A Tunisian official told the Reuters news agency that Abukraa was in Tunisia.