Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Al-Shabab Attacks Military Base Used by US Forces in Kenya Associated Press The U.S. military said the security situation was "fluid" at a Kenyan airfield used by U.S. forces after a pre-dawn attack Sunday by the al-Shabab extremist group. The attack destroyed U.S. aircraft and vehicles, Kenyan authorities said, and at least four attackers were killed. It was not yet clear whether any U.S. or Kenyan forces were killed. A U.S. Africa Command statement said "an accountability of personnel assessment is underway." The midday statement said the Manda Bay airfield was "still in the process of being fully secured." The al-Qaida-linked al-Shabab, based in neighboring Somalia, claimed responsibility and asserted that "intense" combat with U.S. forces continued. The U.S. statement called the al-Shabab claims exaggerated and said U.S. and Kenyan forces repelled the attack. It is the first known al-Shabab attack against U.S. forces inside Kenya, a key base for fighting one of the world's most resilient extremist organizations. A plume of black smoke rose above the base. Residents said a car bomb had exploded early in the morning. Lamu county commissioner Irungu Macharia told The Associated Press that five suspects were arrested and were being interrogated. An internal Kenyan police report seen by the AP said two fixed-wing aircraft, a U.S. Cessna and a Kenyan one, were destroyed along with two U.S. helicopters and multiple U.S. vehicles at the Manda Bay military airstrip. The report said explosions were heard at around 5:30 a.m. from the direction of the airstrip. The scene, now secured, indicated that al-Shabab likely entered "to conduct targeted attacks," the report said. The U.S. military said only that "initial reports reflect damage to infrastructure and equipment." The Kenya Civil Aviation Authority said the airstrip was closed for all operations. Al-Shabab's statement included photos of blazing aircraft it asserted were from the attack. A second al-Shabab claim issued hours later asserted that "intense close-quarters combat" against U.S. forces continued. .