The Green Beret killed in Somalia when his unit came under attack Friday was supporting a broader plan to take territory along the Jubba River back from the al-Shabab affiliate of al Qaeda. And the U.S. military is sounding like it’s sticking with the plan for the long haul.

Special-operations sources told The Daily Beast that the soldier provided intelligence support during a large mission to build a rugged joint base near Kismayo in southern Somalia. The intent was for Somali forces to man the combat outpost the Green Berets are building.

“It’s part of a campaign plan to take back territory along the river,” a special-operations source told The Daily Beast. Yet even as congressional skepticism builds for shadowy U.S. missions on the African continent, the military indicated that the deadly attack, which also wounded four special forces soldiers, will not pause that plan.

The assault lasted less than an hour, sources said, but involved mortar and small-arms fire. And it did not come as a surprise to some in the special-operations community. Al-Shabab typically implants improvised explosive devices along roads and launches indirect fire on adversary forces, but “they go big when we aren’t there,” the source said.

U.S. Africa Command (AFRICOM), which was in charge of the mission, appeared to confirm that building the combat outpost, or COP, was part of a push to roll back al-Shabab’s territorial gains. U.S. forces have been fighting the terror group for 12 years, usually in a support role. There are over 500 U.S. troops there, the most the U.S. has yet deployed to Somalia. The Trump administration has increased the pace of drone strikes in the east African nation while permitting military commanders greater leeway in launching them.

“The mission's objectives were to clear al-Shabab from contested areas, liberate villages from al-Shabab control, and establish a permanent combat outpost designed to increase the span of Federal Government of Somalia (FGS) security and governance,” AFRICOM said in a statement.

AFRICOM’s statement indicated a “large force,” approximately 800 troops from the Somali National Security Forces and their Kenyan Defense Force partners, were building the combat outpost as part of a “multi-day operation,” for which U.S. special forces provided “advice, assistance, and aerial surveillance.”

Asked to clarify, an AFRICOM spokesperson, Lt. Cmdr. Desiree Frame, indicated that the U.S. military is determined to see the campaign, to wrest the Lower Jubba River Valley from al-Shabab, through to completion. The military’s language referred to “clearing and “holding” operations, terminology that recalled U.S. counterinsurgency operations in at the height of the Iraq and Afghanistan wars—this time, without the U.S. in the lead.

“Now that the outpost has been built, our partner forces intend to maintain and hold it in order to enable the FGS [Federal Government of Somalia] to provide a safe and secure environment to the local population,” Frame told The Daily Beast.

“Our partner force intend to hold the COP as originally planned. This operation was always planned to bring along a sufficiently large hold force to maintain a permanent presence in the region.”

AFRICOM’s statement added that of the four soldiers wounded in the attack, three required medical evacuation. The fourth “received sufficient medical care in the field,” the command said.

The special forces soldiers were assigned to the 1st Battalion, 3rd Special Forces Group based at Fort Bragg, North Carolina, sources familiar with the matter said.

Fears said operational security prevented AFRICOM from clarifying the total number of U.S. soldiers contributing to the operation.

The bloody assault comes about eight months after four other special-forces soldiers were killed in Niger in a mission that has prompted AFRICOM to reportedly consider a reduction in forces and a diminished operational pace on the continent.

—with additional reporting by Kevin Maurer