Former US President Donald Trump has slammed Joe Biden for swapping US women's NBA star Brittney Griner for Russian arms dealer Viktor Bout in a deal brokered by Saudi Arabia.

Brittney was freed on Thursday, Dec. 8, after spending nearly a year in Russian captivity as part of a prisoner swap deal with the Biden administration.

Reacting, Trump wrote in a post on his social media website Truth Social: "What kind of a deal is it to swap Brittney Griner, a basketball player who openly hates our country for the man known as 'The Merchant of Death'."

The former president suggested Paul Whelan should have been freed instead of Griner.

Whelan is a former Marine with citizenship in four nations, including the U.S., who was arrested in Russia in 2018 on espionage charges and convicted in 2020, receiving a 16-year prison sentence.

"What a stupid and unpatriotic embarrassment for the USA!" Trump added.

Griner, who was arrested in February for bringing vape cartridges with hashish oil into the country, was released in exchange for Viktor Bout, an infamous Russian arms dealer serving a 25-year sentence for conspiring to kill Americans, leading many critics of president Biden’s administration to say Russia got the better end of the trade.

Trump was President when Mr Whelan was detained on bogus espionage charges just three days after Christmas in 2018. He took no action to free him during his time in the White House when he had the power to do so.

Meanwhile, Trump's national security advisor John Bolton said the trade puts other Americans in danger of being detained by rogue states for bargaining power.