WNBA and former Baylor University star Brittney Griner has been released from Russian detention in a prisoner exchange for convicted Russian arms dealer Viktor Bout.

“She is safe. She is on a plane. She is on her way home,” President Joe Biden tweeted on Thursday morning.

Later at the White House alongside Griner’s wife, Cherelle, he said, “After months of being unjustly detained in Russia, held under intolerable circumstances, Brittney will soon be back in the arms of her loved ones, and she should have been there all along.”

Griner was arrested on drug smuggling charges in February, just days before the Russia-Ukraine war started. She was allegedly caught bringing vape cartridges containing cannabis oil through a Moscow airport as she returned to play for a basketball league in the country.

Griner was sentenced to nine years in prison in early August and was transferred to a penal colony in the Republic of Mordovia, about 300 miles southeast of Moscow, in mid-November after losing an appeal.

The exchange did not include another American citizen whom the State Department has declared wrongfully detained, Paul Whelan.

Whelan, a former U.S. Marine who is also an Irish, British, and Canadian citizen, has been detained in Russia since being arrested at a Moscow hotel in December 2018 for allegedly participating in an intelligence operation.

He was sentenced to 16 years in prison on espionage charges which he and his family have maintained strongly are fictitious.

Biden acknowledged that Whelan will remain imprisoned, saying that Whelan’s family “have to have such mixed emotions today.”

“This was not a choice of which American to bring home,” Biden said. “Sadly, for totally illegitimate reasons, Russia is treating Paul’s case differently than Brittney’s. And while we have not yet succeeded in securing Paul’s release, we are not giving up. We will never give up.”

Cherelle Griner thanked the administration for securing her wife’s release and said she was “overwhelmed with emotions.”

She and Brittney Griner “will remain committed to the work of getting every American home, including Paul, whose family is in our hearts today,” Cherelle Griner added.

The Russian government was reportedly only willing to negotiate for Griner and not for Whelan, an unnamed U.S. official told CNN.

Russia has been handling the cases of Griner and Whelan differently based on what each has been accused of, the official said, adding that the Biden administration repeatedly made offers to get Whelan released as part of this deal.

“It was a choice to get Brittney or nothing,” the U.S. official said.

The Biden administration had notified the Whelan family of Griner’s release before the news broke. The Whelan family expressed happiness at the news that Griner was on her way home.

“There is no greater success than for a wrongful detainee to be freed and for them to go home,” a statement to media outlets read. “The Biden Administration 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.”

But the Whelan family also worries about what the future holds for Paul. Appearing on CNN, Paul Whelan’s brother, David, said he is not confident Paul will survive the rest of his sentence in Russia.

“But we do worry about what’s in Paul’s future,” David Whelan said. “I think it’s become clear that the U.S. doesn’t have any concessions that the Russian government wants for Paul. So, I’m not really sure what the future holds.”

The exchange of Griner for Bout has been floated since back in May.

Bout was in the middle of a 25-year sentence in federal prison after being convicted of conspiracy to kill Americans, acquire and export anti-aircraft missiles, and provide material support to a Colombian terrorist organization.

Dubbed the “Merchant of Death,” Bout’s dealings inspired the Nicolas Cage film Lord of War.

Bout is now back in Russia, the Russian foreign ministry said on Thursday. Moscow had slammed his sentencing in 2012 as “baseless and biased,” and Bout has maintained he is innocent.

Steve Zissou, Bout’s U.S. lawyer, said the prisoner swap between Griner and his client was “fair.”

“As I have urged for some time, given the 15 long years that Viktor Bout has been in custody since the United States government targeted him in 2006, his exchange for Brittney Griner, who has only been in custody for a few months, is fair,” Zissou said in a statement.

Former ambassador John Sullivan, who stepped down as the top U.S. diplomat in Moscow in September, told CBS News that the talks to free Brittney Griner were “extremely difficult negotiations.”

“We’re dealing with a government that isn’t bound by law or morals, our counterparty. It’s not a typical diplomatic negotiation. And my understanding is that the Russians really presented the president, President Biden, with a take-it-or-leave-it proposition. One for one, it was Brittney,” Sullivan claimed, citing conversations with current and former officials. “And unfortunately, we’ve had to leave other Americans, in particular Paul Whelan.”