According to a resident in the port town of Kismayo, planes struck a military convey as it drove along the coastline late Thursday. The resident, Mohamed Aden, said he saw three wounded militants in the city.
Sheik Hassan Yaqub, a leader of the Islamic rebel group al-Shabab, confirmed the attack and said two fighters were wounded.
It was not immediately clear who was behind the strike, but U.S. aircraft have attacked militants in Somalia before. A U.S. airstrike killed a senior al-Shabab leader in 2008, while a U.S. commando raid in 2009 killed the militant wanted for the 2002 car bombing of a Kenyan beach resort.
The overnight strike near Kismayo occurred near a militant camp, leading some residents to assume the camp was being attacked.
"We heard bangs of explosions first and again after minutes, more loud blasts," said Ali Abdinur, a resident, said by phone. "I don't know what happened but the place was an al-Shabab camp."
Yaqub, the al-Shabab leader, talked to a militant-run radio station after the attack.
"Two enemy aircraft attacked our mujahedeen fighters at a time they were conducting a security patrol near Kismayo" he told the radio station.
The airstrikes came less than two weeks after a Somali soldier killed al-Qaida's top leader in Somalia, Fazul Abdullah Mohammed, who was wanted for his role in the 1998 bombings of U.S. embassies in Kenya and Tanzania. Mohammed was carrying sophisticated weapons, maps, and correspondence when he was killed, a potential treasure trove of intelligence about militant activity in Somalia.
The U.S. has a military base in the small nation of Djibouti, which lies directly to the north of Somalia. The U.S. Navy also patrols off East Africa as part of the international anti-piracy effort.
Somalia has not had a functioning government for 20 years, the reason militancy and piracy have been able to flourish in the country.