An air strike near the Somali town of Afgoye killed four people, a relative of one of the victims said on Tuesday.

The United States frequently carries out such attacks that target Islamist militants in the Horn of Africa country. The attacks have helped bolster Somalia’s U.N.-backed central government against al Qaeda-affiliated al Shabaab insurgents.

Abdiqadir Nur, an employee of telecoms firm Hormuud Telecom, and three others died at 1330 GMT while driving through Laanta Buuro village in the southwestern Lower Shabelle region, 45 km (28 miles) from the capital Mogadishu, relatives said.

“Nur and three others died on the spot. His brother Mahad Nur is totally burnt,” Nur’s cousin Abdullahi Ali said.

In an email to Reuters, the U.S. Africa Command (AFRICOM) said it carried out the air strike on Monday and that three militants had died in the attack.

“We are aware of reports alleging civilian casualties resulting from this air strike…The U.S. Africa Command will review any information it has about the incident, including any relevant information provided by third parties,” it said.

Al Shabaab was driven out of Mogadishu in 2011, but retains a strong presence in southern and central parts of Somalia.

Al Shabaab, which wants to impose strict Islamic law in Somalia, says relatives of jihadists killed in air strikes are often motivated to join its ranks.