Somalia on Thursday requested an explanation from the United States on an airstrike which it said had killed 22 people in the centre of the country.
A government statement said the "unfortunate and deplorable" strike had been carried out without the knowledge of the Somali authorities.
The Pentagon earlier admitted to carrying out an airstrike at Galkayo on Wednesday, saying the "counter-terrorism operation" in support of Somali forces had killed nine al-Shabaab Islamists.
Somali regional officials, however, said there were no al-Shabaab militants in the area and that 22 members of the local security forces were killed.
The officials said the US had acted on erroneous information. The strike angered local residents, who staged demonstrations against it.
Pentagon spokesman Jeff Davis said the US was looking into reports that Somali forces were killed.
A Somali intelligence official meanwhile said Somali elite forces supported by US warplanes had conducted a raid on an al-Shabaab-controlled village in the south early Thursday, killing three Islamists including a middle-level commander.
The operation targeted Gole-shumbi village 60 kilometres west of the port city of Kismayo, said the official, who asked to remain anonymous.
The US supports Somalia in its military campaign against al-Shabaab. Thousands of lives have been lost on both sides over a decade of unrest.