ISIS
An Islamic State fighter, waving a flag, cheers as he takes part in a military parade along the streets of Syria's northern Raqqa province, June 30, 2014. REUTERS

The U.S. Department of Justice announced Thursday that it has sued the Islamic State group, also known as ISIS, to recover four Syrian antiquities it believed were stolen by the militant group.

The antiques include a gold ring with a carved gemstone, two gold coins and a neo-Assyrian stone stela. All together, the items are worth hundreds of thousands of dollars.

American authorities learned about the four missing items during a raid on a home of ISIS finance leader Abu Sayyaf in 2015. Several artifacts were found, which “appeared to have been in the process of being sold internationally,” according to the lawsuit.

"For example, the antiquities were cleaned and maintained in a manner consistent with the preparation for sale. Moreover ... Abu Sayyaf's electronic media had multiple photographs of other antiquities. These photographs were staged in a manner consistent with the sale of antiquities," the Justice Department said in the lawsuit.

This is the first time that the U.S. has filed a lawsuit to recover antiquities that are foreign assets of the Sunni hard-line group.

“Other documents on Abu Sayyaf’s hard drive indicate that Abu Sayyaf, on behalf of ISIL, received at least 20 percent of the proceeds of items excavated in ISIL-controlled areas and in some instances personally sold the archeological items. These transactions were often in U.S. dollars. Based on the previously described evidence, the Defendant Properties are subject to forfeiture,” according to the lawsuit.

Authorities have said that it is difficult to know how many antiquities have gone to ISIS. This makes it tough to assess the total cultural loss to Syria and Iraq. Syria’s border with Turkey is thought to be an important place on the smuggling route. However, Turkish officials have seized thousands of ancient relics over the last several years, according to U.S. officials.