A passenger jet and a military helicopter crashed near Reagan National Airport outside Washington and plunged into the Potomac river, triggering a search for survivors in near-freezing temperatures.

The regional flight, operated by PSA Airlines for American Airlines, had originated in Wichita, Kansas. The Bombardier CRJ700 and a US Army Sikorsky H-60 Black Hawk helicopter collided as the jet approached the airport around 9pm.

American Airlines, which wholly owns PSA, said American Eagle flight 5342 carrying 60 passengers and four crew members, “was involved in an accident” at Reagan National. “Our concern is for the passengers and crew on board the aircraft,” the airline added. “We are in contact with authorities and assisting with emergency response efforts.”

Robert Isom, American Airlines chief executive, then released a video saying he was travelling to Washington. “We want to learn everything we can about today’s events. That work will take time,” he said.

Officials would not confirm if there had been any casualties, nor did they confirm if any people had been rescued. Many are feared dead.

Washington’s Metropolitan Police Department said on X that “a multi-agency search and rescue operation is under way” in the Potomac river as about 300 federal, District of Columbia and state responders, including multiple teams of divers, searched for survivors. They were expected to work through the night.

“We’re going to be out there as long as it takes, and we’re obviously trying to get to people as soon as possible,” Washington mayor Muriel Bowser said during a media briefing at the airport early on Thursday. “We are going to recover our fellow citizens.”

A US defence official said there was a crew of three on board the helicopter but no senior personnel. The Black Hawk was on a training flight, according to Heather Chairez, spokesperson for the Army’s Joint Task Force-National Capital Region.

A second defence official said the status of the helicopter crew was unknown. The Army said the Black Hawk was operating out of Fort Belvoir, Virginia, about 20 miles from the Pentagon.

“We are working with local officials and will provide additional information once it becomes available,” the Army said in a statement.

In a statement, US President Donald Trump said he had been “fully briefed on the terrible accident”. He later posted about the crash on Truth Social, saying it could have been prevented.

“The airplane was on a perfect and routine line of approach to the airport. The helicopter was going straight at the airplane for an extended period of time. It is a CLEAR NIGHT, the lights on the plane were blazing, why didn’t the helicopter go up or down, or turn,” he asked.

“Why didn’t the control tower tell the helicopter what to do instead of asking if they saw the plane. This is a bad situation that looks like it should have been prevented. NOT GOOD!!!” Trump added.

Pete Hegseth, Trump’s recently confirmed defence secretary, wrote on X that the Army and defence department had opened an investigation into the crash.

The airport, located near the Pentagon and across from the National Mall, said all take-offs and landings had been stopped but the terminal remained open.

Sirens blared across the US capital as dozens of police cars swarmed both sides of the river near the scene of the crash, closing off roads to traffic, while helicopters with searchlights circled above and boats circled the wreckage.

“I hope they find some people alive,” said Michael Wille, 38, who had joined a crowd on Daingerfield island, just south of Reagan airport, to catch a glimpse of the search and rescue effort. “But it’s been three hours now and the water is very close to freezing point.”

A spokesperson for Sikorsky, which makes the Black Hawk helicopter and is owned by defence contractor Lockheed Martin, said: “We have offered our support to the investigation and our customer.”

MHI RJ Aviation, which acquired the CRJ series of aircraft and supporting operations from Bombardier in 2020, did not immediately respond to a request for comment.

Jerry Moran, a senator from Kansas, told reporters he had lobbied for American Airlines to introduce a nonstop flight from Wichita to Reagan National Airport.

“That flight has been in existence about a year, and it is certainly true that Kansas and in Wichita in particular, we’re going to know people who are on this flight,” he said.