MISRATA, LibyaCol. Moammar Gadhafi's forces launched a surprise ground and artillery attack Tuesday against this city's port, threatening Misrata's sole lifeline to the world just two days after rebels drove the last government forces out of the city.
Opposition forces appeared to be caught off guard when the Libyan leader's forces swept through rugged coastal desert while unleashing a pounding artillery and rocket bombardment against the port and the surrounding area. Col. Gadhafi's forces have so far avoided that approach, presumably because the open terrain provides no cover from North Atlantic Treaty Organization airplanes.
The rebel official in charge of communications at the port, Sadiq Fitury, said rebel commanders alerted NATO, which responded late Tuesday with airstrikes that appeared to halt the counteroffensive.
The attack came days after the government said it was withdrawing its forces from Misrata and would leave the battle for the city to local tribes. It forced rebels back on the defensive after they had repelled government forces from Misrata and were planning to reclaim the city's airport south of the city.
Libya's deputy foreign minister, Khaled Kaim, told reporters in Tripoli he had no information about an attack on the port. He said the army was trying to clear the way for a convoy arranged by local tribes to deliver food and medicine to an enclave between the port and the city center whose residents had been isolated by weeks of fighting.
Mr. Kaim said the rebels had been pursuing and attacking the army for two days since its withdrawal from the city center. After sustaining at least 10 casualties, he said, the government forces had changed course, though he would not confirm their use of artillery. "When you receive attacks, you have to defend yourself," he said. "Otherwise, you die for nothing."
In Washington, U.S. defense officials said NATO has begun stepping up attacks on Libyan command-and-control centers, palaces and headquarters. The expansion of the target list is aimed at undermining the Libyan military's ability to coordinate offensives and resupply its forces, the officials said.
"Those centers are the ones that are commanding the forces that are committing some of these violations of humanitarian rights, such as in Misrata," U.S. Defense Secretary Robert Gates said. "So we consider them legitimate targets."
Mr. Gates said Col. Gadhafi wasn't a target but command-and-control centers were.
Mr. Kaim insisted that NATO was "destroying the infrastructure of the country and trying to assassinate the leader."
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The coastal city of Misrata has been besieged on three sides by Col. Gadhafi's forces for two months. The port is vital as the city's only means of receiving critical resupplies of food, medicine and weapons to sustain the opposition's struggle there.
"If the port falls, we will all die," said Mustapha Ali, a 36-year-old rebel fighter who brought his wounded comrade to the hospital on Tuesday evening.
At one point, port officials communicated frantically with NATO ships offshore when an unidentified ship approached. Rumors swirled among port officials over reports that Col. Gadhafi's forces had planted mines in the port, underscoring their fears of losing the strategic spot.
In previous fights for Misrata's port, Col. Gadhafi's forces have come along the paved urban thoroughfares and were repulsed by the rebels, who have heavily fortified those the main roads.
Government forces have seemed to prefer to operate in urban areas, where they can dodge NATO airstrikes by hiding in civilian neighborhoods.
But while fighting house to house in Misrata's tangled streets, Col. Gadhafi's forces have been outwitted by rebel fighters whose intimate knowledge of their city's landscape has made up for their inferior weapons and training.
Tuesday's attack began with heavy shelling in the early afternoon while an aide ship from the International Committee for the Red Cross was in port evacuating African worker refugees. The shelling forced the ship to sail ahead of schedule before it finished loading the evacuees. Another evacuation ship, chartered by the International Organization for Migration, stayed off shore due to the shelling.
Shortly after the attacks began, rebel fighters manning positions in the desert northeast of the port spotted the invading force. They put out the first calls by walkie-talkies and Thuraya satellite phones to rebel commanders calling for backup, opposition fighters said.
Columns of rebels filled pickup trucks. Some with heavy caliber anti-aircraft machine guns mounted in the back streamed toward the port area throughout the afternoon.
Accounts from several wounded rebel fighters returning from the battle to defend the port put the size of Col. Gadhafi's force at between 200 and 300 soldiers in Land Cruisers and trucks firing rockets.
Among those who had been left behind due to the shelling was a French journalist in critical condition after being shot in the neck by a stray bullet.
One shell struck a camp for African refugees awaiting evacuation near the port, incinerating at least eight refugee tents, killing three refugees and wounding at least 10, said witnesses and medical officials.
The Libyan Iron and Steel Co., located at the port, was billowing black smoke and flames after being struck by a rocket. Julian E. Barnes and Richard Boudreaux contributed to this article.
Write to Charles Levinson at email@example.com