NAIROBI, May 1 -- A top insurgent leader in Somalia whom U.S. officials have accused of having ties to al-Qaeda was killed in a U.S. airstrike early Thursday, according to the Islamist group he led.

The attack in the town of Dusa Marreb in central Somalia leveled a house belonging to the reclusive leader, Aden Hashi Ayro, who was inside at the time with at least one of his top commanders, according to his followers.

A spokesman for U.S. Central Command confirmed that the United States had attacked "a known al-Qaeda operative and militia leader" in the vicinity of Dusa Marreb, about 300 miles northeast of Mogadishu, the Somali capital.

A U.S. military official said five Tomahawk cruise missiles were launched against the village from a U.S. naval vessel. The official would not confirm the type of vessel or its home base but said ships from the Navy's 5th Fleet, based in Bahrain, "routinely operate in the Horn of Africa area."

The group that Ayro headed issued a statement calling him a "martyr."

"We are here informing the Enemy of God" that Ayro's "trained and educated colleagues are currently in operation. They are committed to the continuation of the Holy War," said Mukhtar Robow, a spokesman for al-Shabab, the military arm of the Islamic Courts movement that has gained ground recently against Somalia's weak transitional government and the Ethiopian troops backing it.

The United States recently designated al-Shabab a terrorist organization.

Reports varied on the number of people killed. Abdi Warsame, a headmaster in the area, said he counted 16 bodies strewn around a crater where Ayro's house used to be, on the western outskirts of town.

Over the past year, the United States has carried out five known attacks in Somalia that officials have said were aimed at al-Qaeda operatives. The attacks killed civilians and insurgents fighting what they consider the illegal occupation of their country by Ethiopian troops.

Some analysts say the United States has exaggerated the insurgents' ties to al-Qaeda and are taking sides in a messy civil war at the cost of rising anti-American sentiment in a moderate Muslim country.

Ayro's popularity was built partly on that sentiment.

In recent years, Ayro, believed to be in his late 30s, had become a cultlike figure to the young Somali men who followed him. Like them, he grew up in the checkpoint-and-shakedown culture of 1990s Mogadishu, when predatory warlords brutally ruled the streets. In those years, he became a protege of a key Islamist leader.

A U.S. intelligence official said that although Ayro was not a formal member of al-Qaeda, he served as a conduit and facilitator for extremists in East Africa. His participation in militia fighting in Somalia in the early 1990s "came to the attention of people in extremist circles," the official said. "One of the results of that was that he went to Afghanistan for training" and established contact with the senior al-Qaeda leadership.

On his return to Somalia, he joined a radical faction of the broad Islamic movement that eventually ousted the hated warlords, who had been backed by the United States to deliver terrorism suspects for questioning.

Ayro became a youth leader in his own right, training his young militiamen in a colonial Italian cemetery in Mogadishu. As the Islamic movement rose to power, Ayro earned a reputation for ruthlessness, ordering the killings of a British journalist, four foreign aid workers and a Somali peace activist.

After U.S.-backed Ethiopian troops ousted the Islamic movement in December 2006, he was blamed for introducing suicide bombings, improvised explosive devices and other al-Qaeda style tactics to the insurgency that has gripped Somalia ever since.

U.S. officials alleged that Ayro helped shelter the three al-Qaeda operatives involved in the 1998 bombings of the U.S. embassies in Kenya and Tanzania.

Ayro had been on the run since the Islamic Courts' ouster, but U.S. intelligence sources said they don't believe he ever left Somalia. According to the sources, he continued to train and strategize in and around Mogadishu for al-Shabab.

U.S. counterterrorism officials say they think Africa is a priority for al-Qaeda, and several Africa-based extremist groups have declared their allegiance to the terrorist network. In a series of public pronouncements over the past year, al-Qaeda leader Osama bin Laden and his deputy, Ayman al-Zawahiri, have called for Islamist extremists to travel to Somalia.

But while al-Qaeda operatives are believed to continue to travel to East Africa from Yemen, no cohesive Somali group has emerged.

"Do these kinds of concerns still exist? Yes," the U.S. intelligence official said. But the situation in Somalia has not "progressed as far as al-Qaeda would have liked. No doubt about that . . . there is no group that calls itself al-Qaeda on the Horn of Africa."

Ayro had posed a political problem for the broad-based coalition of former Islamic leaders, intellectuals and other moderate Somalis opposed to the transitional government of President Abdullahi Yusuf and the Ethiopians.

The opposition, which maintains that Yusuf has used the excuse of fighting terrorism to go after his political and business enemies, has sought to distance itself from Ayro in a bid for international legitimacy.

And it was perhaps Ayro's unpopularity among Somalis that was his undoing, said Mohamed Uluso, a political leader within Ayro's powerful Ayr sub-clan. Uluso said Ayro had been in Dusa Marreb to win the support of traditional clan leaders but had had little success.

"The traditional elders had rejected him," he said, adding that they "did not want their legitimate cause to be confused or compromised by the accusations against Ayro."

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