Somali forces supported by U.S. troops shot dead 10 Somalis, including three children, in a village near the capital Mogadishu on Friday, a witness and local officials told Reuters.
The involvement of U.S. troops was confirmed by U.S. Africa Command, which said it was investigating reports of civilian casualties.
The Somali army initially said no civilians were killed and all the dead were members of the al Qaeda-linked al Shabaab militia, which is fighting to overthrow the weak U.N.-backed government and impose strict Islamic law.
It later issued a second statement saying some civilian casualties had been reported.
“We also understand that there are civilian casualties in which the Federal Government is investigating to find out the truth about this. We urge Somali people to cooperate fully with the Government on this matter,” the Somali army said.
The incident is likely to provoke questions in Washington about the growing U.S. footprint in the Horn of Africa nation, which has been torn apart by civil war since 1991. A U.S. Navy Seal was killed in Somalia in May, the first U.S. combat death there since 1993.
The White House has granted the U.S. military broader authority to carry out strikes in Somalia against al Shabaab, in the latest sign President Donald Trump is increasing U.S. military engagement in the region.
But local elders said the keenness to engage left the U.S. open to being unwittingly drawn into clan feuds, stoking tensions between Somalis and the United States.
The village attacked, Bariire in Lower Shabelle, about 50 km (30 miles) from the capital, is at the centre of a feud between two powerful and well-armed clans, lawmaker Dahir Amin Jesow said.
He said those killed were farmers who had armed themselves to defend themselves against the rival group.
“The two clans who fought misinformed the U.S. forces,” he said, adding that one group may have tipped off security forces that the other side were insurgents.
Witness Warsame Wador told Reuters the dead were farmers who had been asleep when the raid began just before sunrise.
“It was this morning when white and Somali forces entered the farm. All the 10 people were asleep and I ran for my life,” he said. “As I ran away I could see four armoured vehicles parked outside.”
Reuters viewed nine bodies at Madina hospital. An injured man later died, medical staff said. The dead children were eight, nine and 10 years old, said clan elder Abukar Osman Sheikh.
“They were sleeping in their farm when U.S. and Somali forces came into their farm and opened fire. Last year, the U.S. killed my people in Galkayo in a deliberate strike. We shall not bury them. We shall no longer tolerate it,” he said.
A September 2016 air strike in Galkayo killed at least 10 pro-government fighters, the U.S. has acknowledged.
Madina hospital was packed with people who said they were relatives of the dead. Insurgents do not typically accompany their dead to hospitals in the capital, which is controlled by the government.
“These dead bodies were innocent farmers,” Ali Nur, deputy governor of lower Shabelle region, told Reuters.
But the Somali National Army (SNA) issued a statement saying that eight insurgents had been killed in an operation carried out with “international partners”.
“The SNA carried out an operation this morning against a farm in Bariire with known al-Shabaab presence,” the statement quoted General Sheegow, commander of the 20th Brigade, as saying.
“Al Shabaab started shooting at SNA forces after our soldiers entered the farm. The individuals shooting at the SNA were al Shabaab fighters, they were not farmers.”