WASHINGTON (Reuters) - The head of U.S. forces in Africa has ordered an additional investigation into an August raid in Somalia by Somali and American forces, the U.S military said on Thursday.

Last month, the U.S. military said it did not kill any civilians when it accompanied Somali forces on a deadly raid in the village of Bariire.

At the time, it described the dead as “enemy combatants” and that they were members of al Shabaab, the al-Qaeda linked insurgent group.

However, eyewitnesses have told Reuters that 10 civilians were killed and that the military had been drawn into a local clan conflict.

In a statement, U.S. Africa Command (AFRICOM) said it had referred the incident to the Naval Criminal Investigative Service after media reports alleged misconduct by U.S. personnel to “ensure a full exploration of the facts given the gravity of the allegations.”

“AFRICOM takes all allegations of misconduct seriously and will leverage the expertise of appropriate organizations to ensure such allegations are fully and impartially investigated,” the statement said.

The United States has stepped up operations in Somalia this year after President Donald Trump loosened restrictions on the military’s operations in March. A Navy SEAL was killed in Somalia in May, the first U.S. combat casualty there since Somali militiamen shot down U.S. Black Hawk helicopters in 1993.

The United States has also ramped up its use of air strikes, conducting twice as many strikes this year as last year.

Somalia has been riven by civil war since 1991. It now has a weak, internationally-backed government, supported by African peacekeepers.