Interested in Pentagon?Add Pentagon as an interest to stay up to date on the latest Pentagon news, video, and analysis from ABC News.
Milliken, 38, was killed Thursday in a remote area approximately 40 miles west of the capital Mogadishu as U.S. forces were conducting an advise-and-assist mission with members of the Somali National Army. The group came under attack in the middle of the night.
He was a senior chief special warfare operator from Falmouth, Maine, according to a press release from the U.S. Department of Defense.
"Senior Chief Kyle Milliken embodied the warrior spirit and toughness infused in our very best Navy SEALs. We grieve his death, but we celebrate his life and many accomplishments," Rear Admiral Timothy Szymanski, Commander, Naval Special Warfare Command, said in a statement Saturday. "He is irreplaceable as a husband, father, son, friend and teammate - and our thoughts and prayers go out to his family and teammates. His sacrifice is a stark reminder that Naval Special Operators are forward doing their job, confronting terrorism overseas to prevent evil from reaching our shores."
U.S. and Somali forces were attacked at some point after arriving by helicopter to the target location, a compound that housed a group of al-Shabaab militants associated with an attack on facilities nearby used by Somali and U.S. military forces.
“We helped bring them in there with our aircraft,” Pentagon spokesman Capt. Jeff Davis told reporters Friday. “We were there maintaining a distance back as they conducted the operation, that’s when our forces came under fire and we had the unfortunate casualty.”
U.S. and Somali forces were ultimately able to return fire and suppress the attack, a U.S. official told ABC News.
No Somali forces were hurt but a Somali interpreter and two U.S. service members were injured.
The United States has about 50 military personnel in the country, Davis said.
The mission was not being carried out under the new expanded authorities granted by the Trump administration for the U.S. military to conduct offensive counterterrorism airstrikes in Somalia targeting al-Shabab, according to the U.S. official.
"Al-Shabab presents a threat to Americans and American interests," U.S. Africa Command said in a statement on Friday. "Al-Shabab's affiliate, al-Qaeda has murdered Americans; radicalizes and recruits terrorists and fighters in the United States; and attempts to conduct and inspire attacks against Americans, our allies and our interests around the world, including here at home.
"U.S. forces are assisting partner forces to counter al-Shabab in Somalia to degrade the al-Qaeda affiliate's ability to recruit, train and plot external terror attacks throughout the region and in America," the statement added.
Al-Shabab is the largest faction working to overthrow Somalia's central government, seeking to establish a society based on Islamic law, known as Sharia. The group pledged allegiance to al-Qaeda in 2012. Several years later, the group debated whether it wanted to change its allegiance to ISIS, which was gaining prominence in Iraq and Syria.
Ultimately, al-Shabab decided not to affiliate itself with ISIS, although a small faction did break away and pledge its allegiance.