Hundreds of emergency personnel are searching the Potomac River after a midair collision between a US Army Black Hawk helicopter and a passenger plane near Ronald Reagan National Airport in Washington DC.
The crash happened just before 9pm, local time.
The Federal Aviation Administration (FAA) has confirmed an American Airlines plane with 64 people on board was approaching the runway at the airport when it collided with a Sikorsky H-60 helicopter.
Three people were on the military helicopter.
Officials have said they do not believe there were any survivors. The initial rescue operation has now changed into a recovery effort.
What happened?
Reagan Airport announced it had halted all take-offs and landings as authorities attended the scene after the incident was reported at 8:47pm.
It is understood the plane was en route from Wichita in Kansas and was approaching a runway at Reagan Airport when the collision occurred.
The helicopter was flying south.
A spokesperson for the Military District of Washington said the helicopter had been on a training flight at the time of the incident, after taking off from Fort Belvoir.
US media outlets have reported air traffic recordings show controllers asking the helicopter if it had the plane in sight, and instructing it to pass behind the landing aircraft.
A crew member on the helicopter reportedly agreed the aircraft was in sight, and requested "visual separation" with the incoming plane, allowing it to fly closer than may otherwise be allowed if the pilots didn't see the plane.
The controllers approved the request.
Shortly after, commotion is heard on the audio, and seconds after that, controllers begin diverting aircraft away from the scene.
The wreckages of both aircraft remain in the Potomac River.
Who was on board?
Four American Airlines crew were on board, as well as 60 passengers.
The helicopter was identified as a Black Hawk military helicopter and had three soldiers on board.
In a statement, American Airlines chief executive Robert Isom said the company had set up a hotline for people who may have loved ones on board the flight.
"Our concern is for the passengers and crew on board the aircraft. We are in contact with authorities and assisting with emergency response efforts," he said.
Ice skating coaches and former world champions Yevgenia Shishkova and Vadim Naumov were on board the plane, according to Russian state media.
Their son Maxim was also feared to have been on board the plane, Russia's TASS and RIA news agencies reported.
The Wall Street Journal said the US Figure Skating Association had confirmed several of their athletes and community were on the flight.
"These athletes, coaches, and family members were returning home from the National Development Camp held in conjunction with the US Figure Skating Championships in Wichita, Kansas," a spokesperson said.
"We are devastated by this unspeakable tragedy and hold the victims’ families closely in our hearts."
Authorities are searching the river, with emergency services describing the conditions as "extremely rough" with intense winds and cold.
Loved ones are anxiously waiting to hear from family members.
Hamaad Raza told local CBS affiliate WUSA that he was at the airport waiting for his wife.
"She texted me that she was landing in 20 minutes," he said.
"The rest of my text didn't … did not get delivered. That's when I realised that something might be up.
"I'm just praying that someone is pulling her out of the river right now."
Where did the crash happen?
Reagan Airport is in the middle of Washington DC, and is one of the most tightly controlled airspaces in the country because of its proximity to official US buildings such as the White House.
[map]It sits close to the Potomac River, a body of water that cuts through the nation's capital and has been subject to freezing temperatures in recent weeks.
Authorities believe the plane was coming in to land at runway 33 before the collision.
Due to the position of the crash, authorities will be working through the night to launch inflatable rescue boats along the George Washington Parkway, just north of the airport, to access the Potomac.
What's next?
A large scale search-and-rescue operation remains ongoing on the Potomac.
First responders have set up light towers from the shore to illuminate the area.
Senator Roger Marshall, of Kansas, said:
“When one person dies it’s a tragedy, but when many, many, many people die it’s an unbearable sorrow.”
Officials did not announce any deaths at an official press conference earlier in the evening and DC Mayor Muriel Bowser would not say whether any bodies have been recovered from the crash.
Washington DC Fire and EMS chief John Donnelly said divers were now searching both aircraft in the Potomac.
The river is 2.4-metres deep where the plane crashed.
"This incident has grown and there is currently about 300 responders working," Mr Donnelly said.
"We have boats from all throughout the region — police and fire boats.
"We will re-evaluate the situation in the morning … but we are out there tonight and we are working."
Defense Secretary Pete Hegseth said the Army and Pentagon had launched an investigation into the mid-air collision.
[tweet]Some passengers have been allowed to disembark from other planes halted on the tarmac while Reagan Airport remains shut.
It is due to open again at 11am local time on Thursday.
