Salvage crews have recovered the bodies of all 67 people killed when a passenger plane and a US Army helicopter collided near Washington and plunged into the Potomac River, officials said Tuesday.

All but one of the bodies have been identified, said a statement from a variety of government agencies involved in the recovery effort after the deadliest US air crash in 20 years.

The statement called the completion of the search for remains a "significant step" toward bringing closure to the families of the people who died in the accident last week.

"Our hearts are with the victims' families as they navigate this tragic loss," the statement said. "We extend our deepest condolences and remain committed to supporting them through this difficult time."

Crews continue working to recover the wreckage of the passenger plane -- a Bombardier CRJ-700 operated by American Eagle airlines -- from the frigid waters of the Potomac.

So far crews have retrieved pieces including the right wing, a center section of the fuselage, part of the left wing, the tail cone and rudder, the National Transportation Safety Board said.

Work to recover the chopper will begin when the plane work is done, the city agencies said.

Sixty passengers on the plane and four crew members were killed in Wednesday's accident along with three soldiers aboard the US Army Black Hawk helicopter.

There were no survivors.

The plane was on a flight from Wichita, Kansas, to Ronald Reagan National Airport in Washington when the collision occurred.

President Donald Trump was quick to blame diversity hiring policies for the accident although no evidence has emerged that they were responsible.

Trump also said the helicopter, which was on a routine training mission, appeared to be flying too high.

According to US media reports, the control tower at the busy airport may have been understaffed at the time of the accident.

The National Transportation Safety Board is expected to compile a preliminary report within 30 days, although a full investigation could take a year.