U.S. officials sent out a warning after Venezuelan President Nicolas Maduro was attacked with explosive drones in a failed assassination attempt.

The Aug. 4 attack targeted Maduro while he was giving a speech in Caracas. He was unharmed but seven soldiers were hurt. It raised concerns worldwide that commercial drones could be used to harm people.

ABC News obtained a bulletin from the FBI, Department of Homeland Security, and National Counterterrorism Center detailing that concern. The bulletin was issued earlier this week.

“An attack could be conducted by one person or several people using a commercially available, off-the-shelf (drone) to target venues which attract large crowds, such as sporting facilities, concerts, and transportation terminals, or public figures," warned the bulletin, according to ABC News.

Those drones could be used to "deliver hazardous payloads, including explosives, chemicals, or biological or radiological agents."

This threat could lead to more drone regulations, which have already been expanded by U.S. lawmakers. DJI, the makers of the drones used in the Venezuela attack, naturally decried this use of its devices. But the company admitted to design news outlet Dezeen, "we have limited ability to control what people do with them."