The al-Shabab extremist group says it attacked a military base used by U.S. and Kenyan troops in coastal Kenya. Kenya's military says the attempted pre-dawn breach was repulsed and at least four attackers were killed.
A witness reports a plume of black smoke rising above the base and says residents are reporting a car bomb exploded.
The U.S. Africa Command confirms the attack at the Manda Bay airfield.
The al-Qaida-linked al-Shabab is based in neighboring Somalia and has launched a number of attacks in Kenya. Al-Shabab has been the target of a growing number of U.S. airstrikes during President Donald Trump's administration.
An al-Shabab statement Sunday asserted that it had inflicted casualties in the raid on the military base in Manda Bay, near the border with Somalia, and destroyed U.S. military equipment, including aircraft.
"The airstrip is safe," the Kenyan military statement said. "Arising from the unsuccessful breach a fire broke out affecting some of the fuel tanks located at the airstrip."
The attack comes just over a week after an al-Shabab truck bomb in Somalia's capital killed at least 79 people and U.S. airstrikes killed seven al-Shabab fighters in response.
Last year al-Shabab attacked a U.S. military base inside Somalia. The extremist group has carried out multiple attacks against Kenyan troops in the past in retaliation for Kenya sending troops to Somalia to fight it. Al-Shabab also has attacked civilian targets in Kenya including buses, schools and shopping malls.
The early Sunday attack comes days after a U.S. airstrike killed Iran's top military commander and Iran vowed retaliation, but al-Shabab is a Sunni Muslim group and there is no sign of links to Shiite Iran or proxies.