The police said the airstrip used by the US marine was destroyed and aircraft were burned.

"There was a lot of gunfire between the militants and soldiers in the military base. Some aircraft and vehicles belonging to the US were burnt," a police officer who declined to be named told Xinhua.

But the Kenyan military said in a statement that the airstrip was safe after soldiers repelled the attack and killed four attackers.

Paul Njuguna, spokesman of the Kenya Defense Forces, said that the Manda airstrip, which is near a military camp that is estimated to host more than 160 US soldiers, is safe after an attempt to raid it by the Somali extremist group was successfully repulsed.

"The attempted breach was successfully repulsed. Four terrorists' bodies have so far been found," Njuguna said in a brief statement.

"The airstrip is safe," he said, adding that "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 ongoing."

Al-Shabab claimed responsibility for the attack in Lamu County, saying their fighters' "suicide infantry" was involved in the attack.

"Our fighters inflicted severe casualties on both US and Kenyan troops, destroyed US military aircraft and vehicles," al-Shabab said in a statement.