The U.S. military in Africa (AFRICOM) reported a "collective self-defense" airstrike against al-Shabab militants -- killing 13 fighters in Somalia.

The airstrike took place in the vicinity of Seiera, approximately 45 kilometers northwest of Kismayo.

AFRICOM said Saturday's airstrike was conducted in support of Somali forces who were engaged by al-Shabab fighters.

"Working with the Somali National Army, U.S. Africa Command's initial assessment is that the airstrike killed 13 al Shabab fighters and that no civilians were injured or killed," AFRICOM said in a statement. "The command will continue to assess the results of this operation and will provide additional information as appropriate. Specific details about the units involved and assets used will not be released in order to ensure operations security."

The U.S. considers al-Shabab the largest and most kinetically active al-Qaida network in the world. Al-Shabab merged with al-Qaida in February 2012.

"[Al-Shabab] has proved both its will and capability to attack partner and U.S. forces and threaten security interests in the region," AFRICOM said.

Meanwhile, al-Shabab militants raided the recently liberated village of Cowsweyne in the central Galmudug state, killing government soldiers early Saturday, security sources told VOA.

According to two security officials who asked not to be identified because they are not allowed to comment on sensitive military operations, the militants attacked the village using explosions from vehicle-borne explosive devices (VBIED) or car bombs, followed by armed militants who engaged in heavy gun battles with government forces.

The state-run Somali National News Agency (SONNA) said government forces repelled the attack and destroyed the VBIEDs.

However, extremist group al-Shabab issued a press release claiming to have "overrun" the base and killing 178 soldiers and capturing prisoners. That claim has not been independently verified.

The situation in Cowsweyne, 60 kilometers northwest of Ceel Dheer town, is still murky more than 24 hours after the attack. A local official described the attack in Cowsweyne as "painful."

Somali government soldiers liberated Cowsweyne on August 22 as the government resumed military operations against al-Shabab to remove the group from central Somalia and push the militants to the south.

Military officials said they are targeting two main towns in the state, Elbur and Galhareri. Elbur was captured without a fight Friday by a large column of Somali forces. Al-Shabab militants have been withdrawing from towns and villages and retreating into the bush with the intention of a prolonged guerrilla war.