WASHINGTON -- The U.S. Justice Department is acknowledging that the FBI, DEA and other federal law enforcement agencies are likely to make increasing use of unmanned aerial drones in the United States.

The department on Friday issued its first written guidelines for domestic drone use and emphasized the need to respect civil and constitutional rights.

The unmanned aircraft already have been used in kidnapping, drug and fugitive cases, as well as search and rescue operations, the department said. They also can be operated relatively cheaply.

The five-page policy document comes 19 months after the agency's inspector general recommended drone-specific policies that consider privacy rights. That report said that unmanned drones raised greater privacy concerns than pilot-operated aircraft because they can fly closer to homes and operate for days at a time.

The department said drones can't be used solely to monitor protests and other constitutionally protected activities.

Annual reviews will make sure the agency is complying with the new policy.

Separately, the Justice Department has defended the use of armed drone strikes to kill American terror suspects abroad.