A helicopter flies Thursday near the crash site of the American Airlines plane after it collided with a U.S. military helicopter near Reagan National Airport. The FAA indefinitely shut down the helicopter corridor on Friday. Win McNamee/Getty Images

The Federal Aviation Authority on Friday indefinitely shut down the low-altitude helicopter corridor near Reagan National Airport where a collision between a U.S. Army chopper and an American Airlines passenger jet led to a crash killing 67 people, according to reports.

The heavily traveled route runs parallel to the airport's flight path, according to the Associated Press.

The report said the military conducts flights in the nation's capital to allow pilots to become familiar with the routes they would take in the event of a major disaster or an attack on the United States that would require them to ferry top government officials from the region.

The Black Hawk helicopter involved in Wednesday's crash was taking part in a training exercise and flew out of Fort Belvoir in Virginia.

The chopper, which contained three soldiers, collided with the American Airlines jet, carrying 60 passengers and four crew, sending both aircraft crashing into the icy waters of the Potomac River.

All 67 people were killed.

President Donald Trump went onto his Truth Social account to blame the Army pilot for the crash, claiming they were flying higher than they were supposed to in the area.

The investigation into the actual cause continues.