Image source, Reuters

Secretary of Transportation Sean Duffy is now speaking.

He says the recovery mission is a joint effort, with the Federal Aviation Administration, Department of Transportation, President Donald Trump and local and state partners all working together in unison

Duffy outlines how people in DC would've noticed last night that conditions were "clear".

Both the helicopter and the flight were flying in a "standard pattern", he says.

Neither the American Airlines flight nor the military helicopter were in an "unusual pattern".

Duffy says that they have located the two aircrafts, and the fuselage of American Airlines craft was inverted and located in three different sections. It is beneath waist-deep water and recovery of it will continue throughout the day.

Image source, Reuters

DC Mayor Muriel Bowser is the first to address reporters.

She begins by expressing her sadness for American Airlines, for the US defence department and for all Americans for "the loss of life that happened with the collision of these aircraft".

This includes, she says, families in Washington as well as Kansas and the mayor thanks responders for their efforts.

She says teams have been working through the night in "tough and heart-breaking conditions" adding "we should all thank them for their heroic efforts".

We're about to hear from officials for the second time since the fatal air crash took place last night in Washington DC.

Earlier on this morning, DC Mayor Muriel Bowser described the search and rescue operation that is under way - we expect an update from her on this.

We'll bring you updates here, and you can also listen to what they have to say by pressing watch live at the top of the page.

Jasmine Boykin
Reporting from Reagan National Airport

As the sun begins to rise in Washington, so does the anticipation.

Moments ago, it was silent in Terminal 1 at Reagan National Airport with even a whisper seemingly too loud.

But with less than 10 minutes until we hear from local officials on what took place last night, the terminal is buzzing.

People are slowly starting to set up the podium and test microphones for DC’s Mayor Muriel Bowser to share the latest details on the search and rescue operation.

As we just noted, our US partner CBS has reported at least 30 bodies have been recovered from the scene. However, plenty of questions still remain.

You can watch the press conference live from 07:30 local time (12:30 GMT) by clicking Watch live at the top of the page.

Stick with us and we'll bring you the latest.

A few more details are coming in from the BBC's partner in the US, CBS.

As we've just reported, at least 30 bodies were recovered by 06:45 local time (11:45 GMT).

We've now also learned that one thing investigators are looking at is why the helicopter was flying at that location and altitude before the moment of the crash.

Emergency responders have recovered at least 30 bodies from the crash scene, BBC's US partner CBS reports.

Ana Faguy
US Reporter

US and Russian figure skaters were among the passengers on board the flight.

"Several" athletes, coaches and family members involved with US Figure Skating were on the flight, the sport's US governing body said in a statement.

Russian citizens were also on board, the Kremlin confirmed - after local media reported that ice skating coaches and former world champions Yevgenia Shishkova and Vadim Naumov were on the plane.

Inna Volyanskaya, a former skater for the Soviet Union, was also on board the flight, according to Russian state news agency Tass.

We don't know the names of any US figure skaters who were on board.

As many as 15 people on the flight may have been involved in figure skating, an unnamed source told the Reuters news agency.

Read more here.

Adam Durbin
Live reporter

To give you a sense of just how difficult a search operation like this is, I have just reached the very end of East Potomac Park, where the Potomac meets the Anacostia River.

There are huge pieces of ice floating in the water as far as I can see in the pre-dawn light.

A police officer has approached me and several other members of the media gathered here to report, asking us to move to another location since we are barely a few hundred metres from the site of the crash.

The aircraft involved in the collision last night were a Bombardier CRJ700 regional jet operated by American Airlines subsidiary PSA Airlines, and a Sikorsky H-60 Black Hawk helicopter.

Bombardier, formerly Canadair, is a Canadian business aircraft manufacturer headquartered in Montreal.

The American Airlines website says its CRJ700 seats 65 people in total. The flight itself was run by American Eagle, a regional network, which consists of six regional carriers and partners with American Airlines.

The US Army UH-60 Black Hawk is built by Sikorsky Aircraft, part of the defence manufacturer Lockheed Martin.

It is powered by twin turbine engines and can carry up to 12 fully equipped, seated troops in combat configuration, according to the manufacturer.

Sikorsky has built more than 5,000 Hawk aircraft for 36 nations worldwide, Lockheed Martin says.

Jasmine Boykin
Reporting from Reagan National Airport

The normal DC commute looked different this morning.

On my way to Reagan National Airport this morning, it was hard not to notice the change in pace in the city. With police and first responder vehicles growing more frequent as I approached closer to the airport, you could tell something was off.

The true scale of the operation was quite evident.

Along my drive in from the neighbouring state of Maryland, there is no doubt the search efforts have grown since the collision took place a few hours ago. Multiple Maryland State Trooper vehicles were driving alongside myself carrying boats heading towards the Potomac River.

While many questions still remain unanswered, there’s no doubt that this is all hands on deck on both the federal and state level.

Adam Durbin
Live reporter

I've just arrived at Hains Point, an area of DC just across the Potomac River from the airport.

Red and blue flashing lights are clearly visible on the water as rescuers search the wreckage and surrounding river.

It's about 4C (39F) and feels colder due to the wind chill, and I can see the impact the temperature is having on the water even in the darkness.

As professionals are combing through the near-freezing water for more victims, they will have almost no visibility due to the gloom and sediment that collects in fresh water so close to the ocean.

A helicopter is lighting the river from above with a huge spotlight. There is a massive rescue operation under way by both air and water.

Sean Dilley
BBC Transport correspondent

Washington’s airspace is intensely busy, playing host to domestic and international traffic flying in and out of Reagan airport and Dulles International.

These two major hubs are within 30 miles of each other – which in aviation terms is a stones-throw.

Mix in Presidential airspace, heavy military traffic and flights around the Pentagon and you have one of the most tightly controlled airspace in the world.

Anyone who’s ever visited DC will know how many low-flying helicopters tour the Potomac – many carry tourists and civilian VIPS, and a great number are operational and military training flights.

The site of the collision is heavily controlled. Passenger airliners must follow fixed flight plans. In uncontrolled airspace, military pilots operate under strict instruction of air traffic controllers but unlike their civilian counterparts, they have freedom to deviate and a duty to “see and avoid” other aircraft.

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Carl Nasman
Reporting from Reagan National Airport

Terminal 1 at Reagan National Airport is very quiet.

Even the large crowd of news media inside Terminal 1 is speaking in hushed tones.

The entire airport has been shut down until at least 11:00 local time (16:00 GMT) while rescuers scramble to find any crash survivors in the icy cold river.

There is a sense that given the severity of the collision and the cold conditions in the river, rescue efforts may be futile.

Tracking the aircraft flight pathspublished at 10:25 Greenwich Mean Time

10:25 GMT

Both the American Airlines flight and the Black Hawk helicopter were transmitting information about their paths and altitude ahead of the crash.

The two aircraft were visible on a tracking website called ADS-B Exchange as they approached each other.

The plane was sending out ADS-B signals, whilst the Black Hawk helicopter was tracked using another system called MLAT.

Aircraft such as these have systems onboard to detect nearby flights, including a Traffic Collision Avoidance System (TCAS).

Doug Rice, a retired American Airlines pilot, told broadcaster NBC that TCAS isn’t effective below 700ft (213m).

Data from the tracking site shows the American Airlines plane had been on a steady descent approaching Ronald Reagan Washington National Airport from the south. The helicopter was flying from the north, along the Potomac River, also on a descending path.

The last recorded altitude of the aircraft just before the impact was around 200ft.

Simon King
BBC weather presenter and meteorologist

While the cause of the crash is still unknown, the moment there is an aircraft incident near an airport, a detailed weather observation is taken.

The investigators will then use this information to determine if the weather had any impact.

We know the crash happened at around 21:00 local time (02:00 GMT), and while there were clear skies with a visibility of more than 10 miles (16km), there were some gusty winds at that time around Washington DC.

The wind was coming in from a west-north-west direction with a speed of 16mph (26km/hr), gusting up to 26mph (42km/h).

The American Airlines flight will have been using Runway 33 (direction 330º) which means it would be near-enough landing into the wind (290º), as an aircraft would normally do.

However, there is still a crosswind component which is something pilots are aware of in any landing.

In this case, the crosswind at the surface was 10mph gusting to 17mph (16-27km/hr). This is well within the limits of the aircraft and ability for a pilot to land in, so I’m sure there would be have been no weather concerns on approach.

Image source, Getty Images

It's just past 04:50 in Washington DC and still pitch black as about 300 responders continue to work in very tough conditions on the Potomac River with parts of the plane submerged by up to 8ft (243cm).

As we've just reported, the water in the river is understood to have some ice and earlier, DC's fire and emergency services chief said the conditions on the river are "extremely rough".

The water temperature - combined with the lack of light and windy conditions - makes the operation "particularly difficult", says Matthew Schanck, founder of a maritime search, rescue and emergency response consultancy in the UK.

"There's ice in the river, it's particularly cold and that makes it very challenging to (rescue) crews," he tells the BBC. With more than 60 people to search for, he says "there's not a lot of time to really try and locate any survivors and rescue them because of the cold".

According to the US National Weather Service, when your body hits cold water, you can go into "cold shock" within the first minute with dramatic changes to breathing, heart rate and blood pressure.

Within ten minutes, you can lose muscle control and hypothermia can set in within 20 to 30 minutes.

American Airlines Flight 5342 was preparing to land on Runway 33 at the Ronald Reagan National Airport last night when it was involved in a collision with a military helicopter.

According to Reuters news agency, the airport - which is the closest to the capital - is the 24th busiest airport by passengers in the US.

The map below gives an idea of the geography of the region.

Sean Dilley
BBC Transport correspondent

Former RAF pilot and broadcaster George Bacon tells the BBC that military aircraft and helicopters routinely fly in close proximity to passenger planes.

Bacon says: "I've flown as a military pilot in the US and I'm somewhat familiar with the airspace around Washington DC. It's highly congested but civilian and military traffic share one radio frequency".

Bacon adds that military pilots enjoy much greater freedom when it comes to navigation than they would over UK airspace: "The military regulate themselves and pilots can choose to fly where they want and need to. In controlled airspace like this, they would still have freedom to take avoiding action, but they would be following the direction of the controller. The emphasis is that they must look - it's known as 'see and avoid'."

This contrasts with civilian airliners, he explains, which are expected to follow fixed flight paths.

Asked about radio traffic alerting the helicopter pilot to the presence of the passenger aircraft in the capital, he says: "It's standard for air traffic controllers to ask simply 'do you see the aircraft?'. There would be a very clear instruction - so this would be down to the pilot of the military helicopter to avoid the commercial aircraft."

He adds: "It's not unusual for military helicopters to be in such close proximity to commercial aircraft. Investigators will establish what's happened and if there are lessons to be learned, there will be an amendment to the procedures."

We’ve just been hearing from someone who lives next to Reagan Washington National Airport. He describes how the busy airspace has now become eerily quiet.

Matthew Cappucci tells our colleagues on the Today programme that he lives about 1km (0.6 miles) west of the airport, under the flight path of planes taking off.

He says that he usually hears planes every 30 seconds but adds that “since the accident…it’s been absolute silence”.

Cappucci says that DC's airspace is very busy because of both commercial and military flights operating in the area.

“The airspace is so tightly governed but also so busy, and I’m not surprised that eventually there was a collision given how many moving pieces there are all the time.”

Cappucci says he didn’t actually hear the collision.

“I knew something was up when immediately my phone began ringing off the hook and I looked out of the window and I’d never seen so many emergency personnel”, he says.