WASHINGTON, Jan 31 (Reuters) - The U.S. Federal Aviation

Administration is indefinitely restricting helicopter flights

near Washington Reagan National Airport after a deadly collision

between an American Airlines ( AAL ) regional jet and Army Black Hawk

killed 67 people.

An FAA official on Friday told Reuters the agency was

barring most helicopters from parts of two helicopter routes

near the airport and only allowing police and medical

helicopters in the area between the airport and nearby bridges.

The FAA official said the restrictions impact Route 1 and

Route 4 near the airport. National Transportation Safety Board

member Todd Inman said Thursday it appears the helicopter at the

time of the collision was transiting from Route 1 to Route 4. He

noted helicopters in the Washington, DC area use a very

well-defined system.

There were 11,000 military helicopter flights annually

within 30 miles of the airport, according to a 2021 government

report.

The helicopter collided with the jet near the airport

Wednesday, with both aircraft

plunging into the Potomac River

. The cause of the crash is under investigation.

The airport

is located in Arlington, Virginia, across the river from

Washington.

The FAA told lawmakers it planned to continue the

restrictions for the foreseeable future as it conducts a

complete evaluation. Lawmakers including Senators Maria Cantwell

and Josh Hawley have questioned the close proximity of the

military and civilian routes.