ISIS militants hold pieces of a Syrian jet near to Raqqa.
An Islamic State militant (left) stands next to residents as they hold pieces of wreckage from a Syrian war plane after it crashed in Raqqa, in northeast Syria, Sept.16, 2014. REUTERS/Stringer

South Korean military officials are concerned that rifles built by its defense industry are being used by the Islamic State group in Syria and Iraq. Officials believe the K-2C rifles were taken from Iraqi military bases during a period when the terror group began a period of mass expansion that involved over-running Iraq's military bases and stealing munitions, weapons and vehicles.

“Due to its short barrel, it seems to be popular with the IS group that engages in street battles” Yang Wook, a fellow of the Korea Defense and Security Forum (KODEF), told the Korea Times, an English-language daily newspaper based in Seoul. Korea had sold the weapons to Iraqi military as part of its restructure.

It's also believed that the rifles are being traded on the black market in Syria and Iraq, meaning that they could be falling into the hands of other extremist groups or rebel factions in the region, according to a respected blogger that offers defense industry analysis.

ISIS, as the terror group is commonly referred to, posted a promotional video last year showing one of its fighters firing the South Korean rifle on a battlefield in Northern Iraq, according to the Korea Times report.

While other countries had admitted their weapons had been looted from Iraqi military stocks, officials that run South Korea's defense acquisition program said that it's not clear if the rifle is actually the K-2C.

“It is hard to tell if it is a K-2C by looking at the photo,” an official from Seoul's Defense Acquisition Program Administration (DAPA) said of the ISIS video and the blogger's picture.

Among the other weapons and vehicles stolen by ISIS are M16 rifles and body armor, hundreds of U.S.-made armored vehicles and other rifles and munitions from Bulgaria, Russia, China and Belgium.