Russia and the United States carried out a dramatic prisoner exchange on Wednesday, trading a Marine veteran jailed in Moscow for a convicted Russian drug trafficker serving a long prison sentence in America, a senior U.S. official and the Russian foreign ministry said.

The surprise deal would have been a notable diplomatic maneuver even in times of peace, but it was all the more extraordinary because it was done as Russia's war with Ukraine has driven relations with the U.S. to their lowest point in decades.

As part of the exchange, Russia released Trevor Reed, a former Marine from Texas who was arrested in the summer of 2019 after Russian authorities said he assaulted an officer while being driven by police to a police station following a night of heavy drinking. Reed was later sentenced to nine years in prison, though his family has maintained his innocence and the U.S. government has described him as unjustly detained.

The U.S. agreed to return Konstantin Yaroshenko, a Russian pilot serving a 20-year federal prison sentence in Connecticut for conspiracy to smuggle cocaine into the U.S. after he was arrested in Liberia in 2010 and extradited to the U.S.

Russia had sought his return for years while also rejecting entreaties by high-level U.S. officials to release Reed, who was nearing his 1,000th day in custody and whose health had recently been worsening, according to his family.

A senior U.S. official, who was not authorized to discuss the matter by name and spoke to The Associated Press on the condition of anonymity, described Reed's case as one of “utmost priority" for the Biden administration, including because of his health. The official noted that Yaroshenko, whose sentence has now been commuted, had already served the majority of his sentence.

“It was a difficult decision but one that we thought was worth it,” the official said.

The Russian foreign ministry said the exchange of Reed and Yaroshenko was “a result of a long negotiation process.”

The two prisoners were swapped in a European country. Though officials would not say where the transfer took place, in the hours before it happened commercial flight trackers identified a plane belonging to Russia’s federal security service as flying to Ankara, Turkey. The U.S. Bureau of Prisons also updated its website overnight to reflect that Yaroshenko was no longer in custody.

Reed was en route back to the U.S., traveling with Roger Cartsens, the U.S. government's special presidential envoy for hostage affairs.

The prisoner swap marks the highest-profile release during the Biden administration of an American deemed wrongly detained abroad and comes even as families of detainees who have met over the last year with administration officials had described them as cool to the idea of an exchange.

In a statement, the Reed family thanked President Joe Biden “for making the decision to bring Trevor home” as well as other administration officials and Bill Richardson, the former U.S. ambassador to the United Nations whom the family said traveled to Moscow in the hours before the Ukraine war began in hopes of securing Reed's release.

Reed was one of several Americans known to be held by Russia, including WNBA star Brittney Griner, who was detained in February after authorities said a search of her bag revealed a cannabis derivative, and Michigan corporate security executive Paul Whelan, who is being held on espionage-related charges his family says are bogus. It was unclear what if any impact Wednesday's action might have on their cases.

Reed's parents scored a rare private meeting with Biden and administration officials last month. They had stood weeks earlier along his motorcade route during a presidential visit to Texas in hopes of attracting his attention, then later demonstrated outside the White House to ask for a meeting.