A US service member was killed Friday in southern Somalia, according to four US military officials.
Four other US service members were wounded when the team came under attack by mortars and small arms from unknown insurgent forces in the area.
The US troops were on a training mission with local Somali and Kenyan forces when the attack occurred.
US Africa Command, which oversees US operations on the continent, issued a statement later Friday confirming the incident, saying it took place in Jubaland, Somalia, about 350 kilometers southwest of the capital, Mogadishu.
One US service member received medical treatment in the field while the three other wounded service members were evacuated, the statement said.
A Kenyan soldier working with the Somali forces being advised by the US team was also wounded in the attack, according to three US military officials.
The three wounded US service members and the Kenyan soldier were evacuated by military aircraft and the US troops are in "stable condition," receiving medical care outside of Somalia, according to one US military official familiar with the operation.
The official said the casualties were caused by the enemy mortar fire.
A US surveillance aircraft was also flying overhead during the incident according to two US officials.
Africa Command said the combined US, Somali and Kenyan force included some 800 troops and was part of a mission in the area tasked with setting up a permanent combat outpost when they came under attack.
The US military official said "dozens" of US advisers participated in the overall operation, adding that while the al Qaeda affiliate al-Shabaab was known to have influence in the area, the local village was seen as friendly to the federal government. It was unclear whether all 800 US, Kenyan and Somali troops were present when the attack took place.
The official added that there were no plans for Somali forces to leave the combat outpost and that they would maintain a presence there.
There are currently about 500 US troops in Somalia who have been there since 2013 advising local forces battling the al Qaeda affiliate al Shabaab. The US estimates that al-Shabaab commands 4,000 to 6,000 active fighters, making it one of the terror group's largest affiliates.
This is the second US military member to be killed in Somalia since the 1993 Black Hawk down incident that resulted in the deaths of 18 American soldiers. In May 2017, a US Navy SEAL was killed while on a mission advising Somali National Army forces.
The casualty, coming less than a year after the death in Niger of four Army special operations soldiers, could raise further questions about the presence of US troops on remote missions in Africa. A Pentagon report found the deaths of the four soldiers, who were ambushed during an operation, were due to a series of military failures, including inadequate training.