(Bloomberg) -- President Joe Biden announced that WNBA star Brittney Griner had been released from detention in Russia, celebrating her one-to-one swap for a notorious arms dealer who had been convicted and imprisoned in the US.

Griner, 32, was exchanged in a trade for Viktor Bout, according to a statement from Russia’s foreign ministry and senior Biden administration officials. The president didn’t mention Bout, known as the “merchant of death,” in his remarks, and acknowledged that his administration has so far failed to achieve the release of another American the US considers unjustly imprisoned in Russia, former Marine Paul Whelan.

“She’s safe, she’s on a plane,” Biden said Thursday at the White House, referring to Griner. “She’s on her way home after months of being unjustly detained in Russia, held under intolerable circumstances. Brittney will soon be back in the arms of her loved ones.”

Tensions between the US and Russia are at their highest since the Cold War over Russia’s invasion of Ukraine and US support for Kyiv, complicating efforts to secure Griner’s release. While celebrated by many Democrats, the deal for Griner drew criticism from some congressional Republicans, who complained that Biden also should have secured Whelan’s release in exchange for Bout.

“Surely an arms dealer is worth two innocent people?” Representative Adam Kinzinger, an Illinois Republican, wrote on Twitter. Senator Rick Scott of Florida, a Republican who has often sparred with the White House, called the trade “disgusting” and “unforgivable” in a tweet.

Russia’s government and allies of President Vladimir Putin meanwhile celebrated Bout’s return to the country. Moscow has sought for years to engineer his release. The United Arab Emirates, where the swap physically took place, touted its own involvement in brokering the exchange and hosting talks between Moscow and Washington.

The Biden administration had sought a two-for-one trade for Bout that would include Whelan, but US officials said the Kremlin refused to consider those terms. While the deal may have fallen short of US hopes, the president was under considerable pressure from Democrats, who rely heavily on the support of Black voters, to secure Griner’s release.

Representative Hakeem Jeffries of New York, a Democrat who will be the minority leader in the next Congress, hailed the trade. “President Biden gets it done. Again,” he wrote in a tweet.

Biden spoke to Griner by phone Thursday morning from the Oval Office, in the company of her wife, Cherelle Griner.

Griner had been sentenced to nine years and moved to a penal colony last month. The Phoenix Mercury basketball star who played in Russia during the off-season pleaded guilty to drug smuggling in July after customs officials found vape cartridges containing cannabis oil in her luggage at a Moscow airport in February. 

Whelan is serving a 16-year sentence in Russia on spying charges that he denies. White House Press Secretary Karine Jean-Pierre said that Russia was unwilling to consider any deal involving Whelan and “there was no way to bring Paul home right now.” Biden instead had to choose between getting Griner back or no one, she and the president said.

“This was not a choice of which American to bring home,” Biden said. He said “Russia is treating Paul’s case differently” from Griner’s and promised Whelan’s family that his administration would continue negotiating for his release.

Whelan’s brother, David, said in a statement that the White House had alerted their family in advance that Paul Whelan would not be included in the exchange.

“That early warning meant that our family has been able to mentally prepare for what is now a public disappointment for us. And a catastrophe for Paul,” he said.

But David Whelan also said Biden “made the right decision to bring Ms. Griner home, and to make the deal that was possible, rather than waiting for one that wasn’t going to happen.”

Russia’s foreign ministry said the US had long refused to include Bout in negotiations for an exchange, but Russia held out and Washington ultimately relented, according to Tass. 

“Bout’s return to Russia was a matter of personal honor for Putin,” said Tatiana Stanovaya, founder of R.Politik, a political consultancy. “The question will be why the US suddenly softened their stance.”

Griner and Bout were both pardoned before the swap took place, which means they don’t have to serve the remainder of their sentences in their home countries, said Tatiana Moskalkova, the Kremlin’s human rights ombudsman, Interfax reported. She called Bout’s return “a true Christmas present,” according to Tass.

A senior Biden administration official told reporters in a conference call that Bout had to receive an act of clemency from the president in order to be released but did not characterize the move as a pardon. Biden also has the power to commute the sentences of federal prisoners, shortening their prison terms without clearing their convictions.

Jean-Pierre said Biden did not issue Bout’s commutation, freeing him from US prison, until American officials confirmed that Griner was safely in the UAE, where the swap took place.

The Kremlin has spent years trying to free Bout, who was sentenced to 25 years in 2012 after being convicted of conspiracy for plotting to sell weapons to a Colombian terrorist group. 

The former Soviet air force officer was arrested in Bangkok in a 2008 sting operation set up by the US Drug Enforcement Administration and brought to New York for trial, amid Russian accusations that he was illegally extradited from Thailand under pressure from Washington.

Final terms of Thursday’s swap were negotiated via the UAE, whose leader, Sheikh Mohammed bin Zayed, visited St. Petersburg in October looking to help deescalate tensions around prisoners as well as other issues including shelling around Ukraine’s Zaporizhzhia nuclear power plant, according to a UAE official who asked not to be identified discussing private deliberations.

The official said UAE is one of the few countries both the US and Russia still trust. The UAE is a key US strategic partner in the region and also has deep business ties with Russia.

The foreign ministries of the UAE and Saudi Arabia issued a joint statement saying that Saudi Crown Prince Mohammed Bin Salman also helped to broker the releases of Griner and Bout. The two were physically exchanged at the Abu Dhabi airport in the UAE.

Jean-Pierre, however, said no third parties mediated the talks.

“The only countries that negotiated this deal were the United States and Russia, and there was no mediation involved,” she said. She expressed gratitude to the UAE for allowing the swap on its territory without acknowledging any Saudi role.

--With assistance from Nick Wadhams, Steven T. Dennis, Jenny Leonard, Nancy Cook and Justin Sink.

(Updates with Karine Jean-Pierre comments beginning in 11th paragraph. David Whelan’s relation to Paul Whelan and the spelling of Moskalkova’s name were corrected in previous versions of this story.)

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