WASHINGTON (AP) — Russia freed WNBA star Brittney Griner on Thursday in a dramatic high-level prisoner exchange, with the U.S. releasing notorious Russian arms dealer Viktor Bout, American officials said. The swap, at a time of heightened tensions over Ukraine, achieved a top goal for President Joe Biden, but carried a heavy price — and left behind an American jailed for nearly four years in Russia.

The deal, the second such exchange in eight months with Russia, procured the release of the most prominent American detained abroad. Griner is a two-time Olympic gold medalist whose monthslong imprisonment on drug charges brought unprecedented attention to the population of wrongful detainees.

Biden’s authorization to release a Russian felon once nicknamed “the Merchant of Death” underscored the escalating pressure that his administration faced to get Griner home, particularly after the recent resolution of her criminal case and her subsequent transfer to a penal colony.

The swap was confirmed by U.S. officials with direct knowledge of the negotiations who were not authorized to publicly discuss the deal before a White House announcement and spoke on condition of anonymity.

n releasing Bout, the U.S. freed a a former Soviet Army lieutenant colonel whom the Justice Department once described as one of the world’s most prolific arms dealers. Bout, whose exploits inspired a Hollywood movie, was serving a 25-year sentence on charges that he conspired to sell tens of millions of dollars in weapons that U.S officials said were to be used against Americans.

The Biden administration was ultimately willing to exchange Bout if it meant Griner’s freedom. The detention of one of the greatest players in WNBA history contributed to a swirl of unprecedented public attention for an individual detainee case — not to mention intense pressure on the White House.

Griner’s arrest in February made her the most high-profile American jailed abroad. Her status as an openly gay Black woman, locked up in a country where authorities have been hostile to the LBGTQ community, infused racial, gender and social dynamics into her legal saga and made each development a matter of international importance.

Her case not only brought unprecedented publicity to the dozens of Americans wrongfully detained by foreign governments, but it also emerged as a major inflection point in U.S.-Russia diplomacy at a time of deteriorating relations prompted by Moscow’s war against Ukraine.