Emergency responders have recovered at least 30 bodies from the crash scene, a law enforcement source told the BBC's US partner CBS.

The American Airlines flight from Wichita, Kansas, was approaching Ronald Reagan National Airport at around 21:00 local time (02:00 GMT) on Wednesday when the two aircraft collided.

Three US army soldiers were on board the Black Hawk helicopter, a defence official said.

Several "athletes, coaches and family members" were returning from a development camp, US Figure Skating, the sport's American governing body, said in a statement.

Russia confirmed the former world champions Vadim Naumov, 55, and Evgenia Shishkova, 52, who are also married, were on the plane.

The Pentagon said the helicopter, a Sikorsky H-60, took off from Fort Belvoir in Virginia.

An official said it was on a training flight and belonged to B Company, 12th Aviation Battalion from Fort Belvoir in Virginia.

Multiple federal and local agencies are involved in the rescue mission.

At the scene, the BBC observed debris believed to be from the aircraft floating in the Potomac River. US media says the aircraft split in half when it crashed into the water.

BBC Verify confirmed both the plane and the helicopter were transmitting information about their flight paths and altitude ahead of the crash.

They would have used an on board Traffic Collision Avoidance System (TCAS) to detect nearby flights, but Doug Rice, a retired American Airlines pilot, told broadcaster NBC these systems are not effective below 700ft (213m).

The Federal Aviation Administration (FAA) said it would investigate the incident, together with the National Transportation Safety Board (NTSB).

Eyewitnesses told local media they saw sparks and flashes when the mid-air collision happened.

Ari Schulman told NBC Washington what unfolded before him quickly changed from "completely normal" to "very, very wrong".

He said there was "a stream of sparks" underneath the jet.

BBC Transport correspondent Sean Dilley described DC's airspace as "intensely busy".

With two major airports, heavy military traffic around the Pentagon and a Presidential airspace it is "one of the most tightly controlled airspace in the world", he said.

Asked at a news conference how many people have been rescued or recovered, Washington DC's mayor Muriel Bowser said she could only confirm the number of passengers on each aircraft.

The city's emergency chief John Donnelly said 300 responders on rubber boats were deployed to search for survivors.

"There is wind, there are pieces of ice in the water...and because there is not a lot of light, you are out there searching every square inch of space," he said.

"These are very tough conditions for [rescuers] to dive in."

US President Donald Trump said he had been "fully briefed on the terrible accident".

"Thank you for the incredible work being done by our first responders. I am monitoring the situation and will provide more details as they arise," he said in a statement.

He also questioned how the incident could have happened, writing on TruthSocial that it "should have been prevented. NOT GOOD!!!"

Takeoffs and landings have been halted at Washington National as emergency personnel respond to the incident, the airport wrote in a post on X.

Transportation Secretary Sean Duffy, whose appointment was only recently confirmed said "there will be a review of what happened here tonight".

He said the government will take "appropriate action if necessary" to alter flight paths near Ronald Reagan airport.

Flights are being diverted to Dulles International Airport about 28 miles (45km) away, and the Washington DC metro system will stay open late to run extra trains to transport disembarking passengers into the city, a spokesperson from the transport authority said.

Federal aviation authorities and the US Congress have launched investigations into the incident.

American Airlines CEO Robert Isom expressed his "deep sorrow" and said the airline had sent a team to Washington DC, and he will be travelling there too.