Fighting Flares on 2 Fronts in Libyan City

Government forces attacked a convoy of rebel fighters and supply trucks at the checkpoint at Wazen in midmorning, said Tarek Bodrani, the fighter, who was reached by telephone. Mr. Bodrani said a pro-Qaddafi force with about 30 vehicles struck from the north and south, and seven pickup trucks carrying antiaircraft machine guns followed rebels toward the Tunisian town, Dhiba, roughly three miles away.

One government pickup truck crashed and the others were stopped, and the pro-Qaddafi soldiers were detained after being confronted by a roadblock operated by the Tunisian military and local residents. Col. Ahmed Omar Bani, a rebel spokesman, said Colonel Qaddafi’s forces fired mortar shells onto Tunisian soil during the chase.

Outraged Tunisian officials summoned a Libyan envoy to complain about the incursion, Al Jazeera reported. Libyan ordnance reportedly fell in Tunisian territory on Thursday as well, when fighting for control of the Wazen post began, wounding some civilians and potentially further imperiling the Libyan government, which is already fighting on multiple fronts and facing a NATO air campaign.

The rebels had captured the post with hopes of opening a supply route for opposition fighters battling Colonel Qaddafi’s troops in Libya’s western mountains. The fate of that ambition is now unclear, as was the status of the captured Libyan soldiers.

In Libya’s most violent area, in the besieged coastal city of Misurata, fighting erupted across a broad front along the city’s south and west, as rebel fighters pressed toward the city’s airport and faced a fresh ground attack on their western flank.

The fighting in Misurata began early in the morning and raged throughout the day. The city’s edge became a cacophony of machine-gun and mortar fire, punctuated by the rolling explosions of ground-to-ground rocket strikes in neighborhoods behind the front lines.

As the two sides fought, Misurata’s troubles appeared to deepen further as NATO said that pro-Qaddafi forces had been caught Friday mining the waters around the harbor to harass traffic from the sea, which has been the sole lifeline for a city otherwise cut off by loyalist ground troops.

Three mines were discovered and were being disposed of, NATO said in a statement, adding that the devices were being laid two to three kilometers offshore when the inflatable boats on which they were being carried were deliberately sunk.

At least one vessel with humanitarian aid scheduled to enter the port on Friday delayed its arrival and waited off the coast for an all-clear sign from NATO, medical officials in the city said.

Supplies from the sea have been integral to the city’s survival during the two-month siege, as internationally chartered aid ships have delivered food, water, medicine and ambulances, and evacuated thousands of migrant workers and many wounded Libyans in need of treatment not available in the city.

A flotilla of rebel fishing vessels and tugboats have also smuggled in weapons, ammunition and other military equipment, allowing the sparsely supplied rebels to push forward against Colonel Qaddafi’s conventionally equipped troops.

The fighting on two fronts in the Misurata area on Friday appeared to signal simultaneous thrusts, in different places — one by the rebels and the other by loyalist troops.

The loyalists, backed by at least three tanks, struck first, trying to push into and through the village of Zawit al-Mahjoub early in the morning, fighters and medical officials said. The rebels repelled the attack, but not before three tanks entered the village, six rebel fighters were killed and at least 10 more were wounded, a doctor treating them said.

As the battle in the village continued, rebel groups were pushing southward toward the airport, which is still held by the loyalists, and meeting stiff resistance from Colonel Qaddafi’s troops dug in around the airfield or garrisoned within.

By midmorning, a large battle had been joined, and mortar fire was landing, in explosion after explosion, near rebels clustered and hiding in buildings and behind walls.

C. J. Chivers reported from Misurata, and Scott Sayare from Tunis. Stephen Castle contributed reporting from Brussels, and Kareem Fahim from Benghazi, Libya.