American forces in Iraq fought their first real battle against the Islamic State group on Sunday night after the militants attempted to take over a base.

Using light and medium weapons along with the help F 18 jets, U.S. and Iraqi troops fought off the surprise attack on the Ein al-Asad military base, decimating the Islamist group, Shafaq News reported.

The two-hour long surprise attack took place between 1 a.m. and 3 a.m. on Sunday night, leaving an unknown number of ISIS fighters dead and the rest of the militants retreating.

More than 100 U.S. military support troops are stationed at the base and intervened in the fight after "ISIS started to come near the base, which they are stationed in, so [it was] out of self-defense," tribal leader Sheikh Mahmud Nimrawi was reported as saying.

"We have made progress in [the] al-Dolab area, in which ISIS has withdrawn from to the village beyond, after the battles which involved a private American force ... and opened hubs around the region enabling them to storm and surprise ISIS fighters," he added.

The group repeatedly attacked the same base in October, before U.S. troops arrived, reported the Daily Mail.

Located deep inside the country near the front lines of the fight against ISIS, Ein al-Asad was the largest air base located in Iraq's Anbar province during the Iraq War, but has recently been scaled down in size, according to The Daily Mail.

Kurdish forces are currently fighting to retake the town of Sinjar in northwest Iraq after an overnight air attack on ISIS positions, according to Kurdish officials, who said its fighters have pushed back ISIS out of at least eight sub-districts in the Zumar area, reported Daily Mail.