Security forces have arrested five suspected Al-Shabaab militants after the dawn attack at Camp Simba base in Lamu.
The arrest comes barely 48 hours after another militant was captured alive at Lamu, not far from the scene of Sunday's attack.
Camp Simba hosts elite US Marine corps and the Kenya Defense Forces. It was officially elevated to a US base in August 2019.
At the same time, Manda Airstrip has been temporarily closed as soon as forces intensified the crackdown against the militants.
Through US Africa Command, the US military on Sunday confirmed the attack which comes barely 48 hours after yet another attack within the vicinity which targeted buses.
KDF spokesman Col Paul Njuguna on Sunday said the attack was successfully repulsed, adding that close to four suspected Al-Shabaab militants had been killed.
Manda Airstrip, Col Njuguna said, has since been secured, adding that it was an attempted breach of security at the base.
"This morning at around 5:30 am an attempt was made to breach security at Manda Air Strip. The attempted breach was successfully repulsed. Four terrorist bodies have so far been found," he said in a post on Facebook.
"The airstrip is safe. Arising from the unsuccessful breach a fire broke out affecting some of the fuel tanks located at the airstrip. The fire has been put under control and standard security procedures are now on-going."
US troops began operations at Camp Simba in 2017, performing counter-terrorism and border security operations to aid Kenya.
It essentially became a permanent US military installation on August 26, 2019, when the #American flag was raised over the facility.