(CNN) Kenya's military said it killed at least four terrorists Sunday in repelling an attack on an airstrip located near a US military base.

A US service member and two civilian contractors working for the Defense Department were killed in the attack, according to US Africa Command.

In a statement, Kenya's Defense Forces (KDF) said there had been an attempt to breach security at Manda Airstrip -- which is near the Camp Simba US base -- but it had been "successfully repulsed."

"Four terrorists' bodies have so far been found," the KDF said in the statement. "The airstrip is safe."

Al Qaeda affiliate al-Shabaab claimed responsibility for the attack in Lamu county, near Kenya's border with Somalia.

US Africa Command -- which is responsible for military relations with nations on the continent -- said Africa Command and Kenya Defense forces repelled the attack. Africa Command later reported the US deaths.

"Working alongside our Kenyan partners, the airfield is cleared and still in the process of being fully secured," Africa Command said Sunday.

Al-Shabaab said the base was used by both American and Kenyan military personnel, and that US military equipment was "destroyed," according to a statement released by the terror group Sunday. Al-Shabaab provided no evidence to support those claims.

"Al-Shabaab has put out multiple press releases exaggerating the security situation on the ground. This practice has proven common place for this terror organization," the Africa Command said.

The airstrip near Camp Simba is also a tourist site frequented by Western visitors to Kenya.

US Air Force airmen from the 475th Expeditionary Air Base Squadron conduct a flag-raising ceremony at Camp Simba, Kenya, on August 26, 2019.

A fire broke out as a result of the breach and affected some fuel tanks at the airstrip, although the blaze was put out, the KDF said.

CNN has reached out to the State Department, the Pentagon, and the US Embassy in Nairobi for comment.

The Somali government, in coordination with US Africa Command, has conducted several retaliatory airstrikes on al-Shabaab targets in recent weeks.

What is Camp Simba?

US troops began operations at Camp Simba in 2017, performing counter-terrorism and border security operations to aid Kenya, according to a US Air Force news release.

It essentially became a permanent US military installation on August 26, 2019, when the American flag was raised over the facility in what the Air Force said signified its "change from tactical to enduring operations."

"The flag flying here today over Camp Simba symbolizes the permanency of our mission and our dedication to our partners," Lt. Col. Cody Smith, commander of the 475th Expeditionary Air Base Squadron, said in August.