One U.S. military service member and two American contractors were killed in an attack by Somalia’s al-Shabab militant group. The predawn attack targeted an airstrip located on Kenya’s coast. Two other American contractors were wounded in the attack on a military base used by both U.S. and Kenyan forces near the border with Somalia.

“The wounded Americans are currently in stable condition and being evacuated,” U.S. Africa Command said in a statement. Five militants were killed, according to the Kenyan military. Witnesses said the attack by the al-Qaida-linked group lasted around four hours.

UPDATE: U.S. Statement on Manda Bay Terrorist Attack - https://t.co/iO01z8Zpg4 pic.twitter.com/Rpx1xwFkZ1 — US AFRICOM (@USAfricaCommand) January 5, 2020

The attack on Manda Bay Airfield in Lamu county marked al-Shabab’s first attack against U.S. forces in Kenya, notes the Associated Press. Although it remains unclear how the attack unfolded, “pictures of the aftermath indicated that al-Shabab was able to detonate explosives where U.S. military equipment such as helicopters and other aircraft would have been stationed,” reports the Washington Post. Citing a report from Kenyan police, Reuters says the attackers “destroyed two planes, two U.S. helicopters and multiple American military vehicles during their assault.”

The attack came a little more than week since a truck bomb in Somalia’s capital killed at least 79 people.