The al-Qaida-linked al-Shabab militant group on Sunday attacked Kenya's Manda Bay Airfield, a military base that houses US and Kenyan troops.
Al-Shabab claimed the attack destroyed US equipment including aircraft and vehicles, posting photos of a blazing aircraft.
A second al-Shabab claim issued hours later asserted that "intense close-quarters combat" against US forces continued.
"Seven aircraft and three military vehicles were destroyed in the attack," al-Shabab said.
The US Africa Command said in a statement that "the airfield is cleared and still in the process of being fully secured," adding that the situation was still "fluid."
"Al-Shabab has put out multiple press releases exaggerating the security situation on the ground. This practice has proven common place for this terror organization."
The US later confirmed that one US military service member and two contractors were killed in the attack. Two US citizens from the Department of Defense were also injured in the attack.
"The wounded Americans are currently in stable condition and being evacuated," the US military's Africa Command said in a statement.
Key military base targeted
Sunday's attack was the first known al-Shabab attack against US forces inside Kenya, a key base for fighting one of the world's most resilient extremist organizations.
The group has been the target of a growing number of US airstrikes inside Somalia during US President Donald Trump's administration.
Sunday's attack comes a week after a US airstrike against al-Shabab killed at least four "terrorists," US Africa Command said in a statement.
"In coordination with the federal government of Somalia, US Africa Command conducted three airstrikes in two locations targeting al-Shabab militants in the vicinity of Qunyo Barrow and Caliyoow Barrow, Somalia, respectively, December 29," AFRICOM said.
The US strike came one day after a busy area in Somalia's capital, Mogadishu, was rocked by a car bomb that killed at least 79 people.
kw/stb (AP, Reuters)