The Federal Aviation Administration said Monday it will bar drone flights over seven major U.S. nuclear sites, including Los Alamos National Laboratory in New Mexico.

The move is the latest in a series of growing restrictions on unmanned aerial vehicles over U.S. sites that have national security implications.

The new restrictions begin Dec. 29 and include the Hanford Site in Washington State, Idaho National Laboratory, Savannah River National Laboratory in South Carolina, Pantex Site in Texas, and the Y-12 National Security Site and Oak Ridge National Laboratory in Tennessee.

The FAA said it is considering additional requests from other federal security agencies to bar drones.

Earlier this year, the FAA banned drone flights over 133 U.S. military facilities. The Pentagon said in August that U.S. military bases could shoot down drones that endanger aviation safety or pose other threats.

The FAA also banned drone flights over 10 U.S. landmarks in September, including the Statue of Liberty in New York and Mount Rushmore National Memorial in South Dakota, at the request of national security and law enforcement agencies.

It separately barred drone flights over the USS Constitution in Boston, the Gateway Arch in St. Louis and Independence National Historical Park in Philadelphia. The list also includes Glen Canyon Dam in Arizona, Hoover Dam in Nevada and Grand Coulee Dam in Washington state.

Last week, the National Transportation Safety Board said a September collision between a small civilian drone and a U.S. Army helicopter was caused by the drone operator’s failure to see the helicopter because he was intentionally flying the drone out of visual range.

The incident between a U.S. Army UH-60M Black Hawk helicopter and a DJI Phantom 4 drone near Staten Island, New York, occurred as concerns mount over the rising number of unmanned aircraft in U.S. airspace.

The helicopter landed safely, but a 1 1/2-inch (3.8-cm) dent was found on the leading edge of one of its four main rotor blades and parts of the drone were found lodged in its engine oil cooler fan. The Army said previously the helicopter was not targeted and that it was struck by a drone being operated by a hobbyist.

Government and private-sector officials are concerned that dangerous or even hostile drones could get too close to places like military bases, airports and sports stadiums.