Joe Biden has faced pressure from within his own administration, as well as his political opponents, in securing the release of basketball player Brittney Griner from Russia, according to reports.

On Thursday, Biden hailed the “intense and painstaking negotiations” that led to the release of Griner in a prisoner swap deal with the arms dealer Viktor Bout. Griner was arrested at a Moscow airport in February for possession of a small amount of cannabis oil, while Bout, nicknamed ‘the merchant of death’, was serving a 25-year sentence in federal prison for fueling conflicts in Africa and the Middle East.

The large discrepancy between these two offenses led the US Department of Justice to believe the prisoner swap was a mistake, according to a report in the Washington Post. One department official told the Post that “trading a notorious international arms dealer for a basketball player is madness”.

Critics of the tense political and diplomatic trade-off in the prisoner swap have highlighted the case of Paul Whelan, a US marine veteran who is serving a 16-year sentence in Russia on espionage charges. Biden said that “we’ve not forgotten about Paul Whelan, who has been unjustly detained in Russia for years” and blamed Russia for treating his case differently to Griner’s for “totally illegitimate reasons”.

Russia refused to release Whelan along with Griner unless one of its former colonels and alleged spy, Vadim Krasikov, was also released from custody in Germany, according to CNN. Germany was unwilling to do this and the US’s offer of other potential Russian prisoners was rebuffed by Moscow, the report states.

These complex equations between two countries currently at odds over Russia’s invasion of Ukraine has anguished Whelan’s family, who say they fear the conditions may not be right for him to return to the US for several years. David Whelan, his brother, did say, however, that the Biden administration made the right decision to secure Griner’s release.

The situation has been used by Republican leaders and rightwing media to attack Biden, with Kevin McCarthy, the Republican leader in the House of Representatives, warning that Bout will soon return to arms dealing.

“He was convicted of conspiring to kill American law enforcement,” McCarthy said. “His release is a gift to Vladimir Putin and a threat to American lives. Leaving Paul Whelan behind for this is unconscionable.”