Updated

Lawmakers say before thousands of civilian drones begin flying in U.S. skies, Congress should take steps to protect privacy and prevent terrorists from taking over the aircraft.

House members from both parties said at a hearing Thursday they're worried about potential privacy and security threats as the use of small unmanned aircraft becomes widespread.

The Federal Aviation Administration forecasts an estimated 10,000 civilian drones will be used in the U.S. within five years.

Texas Republican Rep. Michael McCaul complained that no federal agency is willing to regulate the drones to protect privacy. The Department of Homeland Security declined to testify at the hearing.

Witnesses also told lawmakers the signals used to guide civilian drones can be hacked, causing them to crash.