Islamic State militants seized Thursday most of the western Iraqi town of al-Baghdadi, in an attempt to break into an air base where U.S. Marines are training Iraqi troops, according to reports. Al-Baghdadi, 85 km northwest of Ramadi in Anbar province, has been besieged for months by IS Jihadists who captured vast swathes of Iraq in 2014. "Ninety percent of al-Baghdadi district has fallen under the control of the insurgents," district manager Naji Arak told Reuters. Militants invaded al-Baghdadi early Thursday amid fierce gun battles with Iraqi troops, according to intelligence sources. Another group of insurgents attacked the Ain al-Asad air base five km southwest of the town, but failed to seize it. About 320 U.S. Marines are training members of the Iraqi 7th Division at the base, as part of the U.S. long term strategy to train 'moderate' opposition to counter the expansion of IS in the region. The base has been struck by mortar fire at least once since December.