U.N. Forces in Somalia Attack Military Power of Warlord for 4th Time : Africa: Aidid’s headquarters are shelled by U.S. gunship. House-to-house searches could be next step.

MOGADISHU, Somalia — U.N. forces launched their fiercest strike yet against warlord Mohammed Farah Aidid’s military power early today, shelling his headquarters from an American AC-130H Spectre gunship.

Helicopters flew cover as the gunship, invisible against the night sky, began a four-hour barrage of 105-millimeter shells at 1:30 a.m. (3:30 p.m. PDT).

An official at the White House, asked whether the gunship was striking at Aidid’s headquarters, said, “I can confirm that.”

Aidid’s house was surrounded by U.N. ground troops. An armored column from Mogadishu’s port area moved toward Aidid’s headquarters but stopped about a mile away as the air attack continued.

Pentagon sources added that U.N. ground forces “might start some house-to-house searches in Mogadishu” today, presumably looking for weapons caches or for Aidid himself. But the White House source said there were indications that Aidid had left Mogadishu.

The nighttime air strike was the first since Monday and the fourth in a string of attacks by U.S.-led forces in retaliation for the killing of 23 U.N. peacekeeping troops from Pakistan on June 5. The United Nations has accused Aidid of orchestrating ambushes that killed the soldiers and injured more than 50.

U.N. sources, speaking on condition of anonymity, said poor weather had prevented attacks on Aidid’s weapons storage areas Tuesday and Wednesday.

Foreign aid workers, seeking refuge in a residence near the target area, said the night attack was accompanied by loudspeaker appeals to people in the area to lay down their arms. They said the appeals in Somali and English told residents they had 10 minutes to flee the area, but no civilians were seen leaving the neighborhood.

On Wednesday, Pentagon officials said four Navy ships carrying assault helicopters and 2,200 Marines were steaming south toward Somalia. They said the task force, which had been put on standby last Friday, had cut short maneuvers in the Persian Gulf off Kuwait and was in the northern Arabian Sea.

Although the ships do not yet have orders to proceed to Somalia, they were headed that way “as a precautionary measure,” officials said. They could reach the vicinity of the troubled nation by the weekend and would afford American and U.N. commanders a potent force of ground troops if fighting in Somalia escalates.

Until the early morning attack, however, Mogadishu and the Somali countryside were quiet enough that many foreign relief workers, evacuated after the Pakistani peacekeepers were killed, began returning to their posts.

Although a pro-Aidid demonstration was staged Wednesday, “there were no reports . . . of violence,” said State Department spokesman Mike McCurry.

At a photo session in the White House Rose Garden, President Clinton reiterated his support for the Somalia mission. “The fundamental mission of the United Nations in Somalia has not changed and I still believe it’s a very important one,” he said.