If terror groups in the Middle East want more weapons to aid their fight against the U.S. military and its allies in the region, they won’t get them from the Pentagon.

It may seem obvious that the Defense Department wouldn’t arm its enemies, but that didn’t stop lawmakers from including a provision in the final fiscal 2019 defense authorization bill that forbids the U.S. military from assisting three terror organizations with a presence in Syria.

“None of the funds authorized to be appropriated by this Act or otherwise made available to the Department of Defense for fiscal year 2019 may be used to knowingly provide weapons or any other form of support to Al Qaeda, the Islamic State of Iraq and Syria (ISIS), Jabhat Fateh al Sham, or any individual or group affiliated with any such organization,” the conference report on the bill says.

The measure stems from Rep. Tulsi Gabbard’s “Stop Arming Terrorists Act,” which the Hawaii Democrat introduced last year with bipartisan support. Gabbard, a skeptic of previous efforts by the U.S. government to train and equip so-called moderate rebels in Syria, believes the measure will ensure that American weapons won’t end up in the wrong hands.

“The United States has both directly and indirectly provided support to armed militants who are either allied with or fighting under the command of terrorist groups like ISIS or al Qaida, particularly in Syria,” Gabbard said. “My introduction of that provision within the defense bill was another effort to ensure that our taxpayer dollars are not being used in that way.”

Kentucky Republican Rand Paul has introduced companion legislation in the Senate.

Gabbard’s call to block U.S. weapons from ending up in terrorists’ hands comes around nine months after U.S.-backed forces ousted the Islamic State from Raqqa, Syria, which the group claimed as its capital city.

Recent reports, though, indicate that Islamic State fighters have likely remained in Syria. These Islamic State holdouts have reportedly blended into the local population with the goal of fighting to regain their lost territory, an event that would only intensify the already bloody Syrian civil war.

The Pentagon may still rely on local forces to push back against a potentially resurgent Islamic State, but will need to first show Congress how they plan to do so.

The defense bill, commonly referred to as the National Defense Authorization Act, or NDAA, requires the Pentagon to describe in a report how it plans to train and equip “appropriately vetted Syrian opposition forces.”

The bill authorizes $300 million for a train-and-equip program for Syrian opposition forces that fight terror groups in that country. The money, though, will remain unavailable until Congress receives that report and the administration’s delinquent Syria strategy, which was due to Congress Feb. 1.