(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.

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