US troops accompanied Somali forces in a helicopter raid against Shebab insurgents in Somalia, a Pentagon spokesman said Wednesday.
US aircraft were used in the operation, which the spokesman described as an "advise, assist and accompany mission" with the Somali army.
"We did go on the mission but we did not go all the way to the objective," Navy Captain Jeff Davis said.
The raid overnight Tuesday to Wednesday came just days after US warplanes and drones killed an estimated 130 Shebab fighters training for a major operation, according to the Pentagon.
Special forces operatives in two helicopters targeted the Shebab-controlled town of Awdhegele, about 50 kilometers (30 miles) west of Somalia's capital Mogadishu, Somali government officials and a Shebab spokesman said.
"We have reports Shebab militants suffered casualties," local district commissioner Mohamed Aweys told reporters.
It was not immediately clear what the objective was, but helicopter raids in the past have been hostage rescue missions, such as a US commando operation in 2012 to free two aid workers who had been held for three months by the group.
Shebab has stepped up their attacks since the start of the year.
Davis said there are a small number of US troops in Somalia supporting an African Union mission and the Somali national army "specifically in their fight against al-Shebab."
"And part of that mission is to conduct enabling missions on occasion," Davis said.