White House spokesman John Kirby said the Russian government would not have agreed to release former U.S. Marine Paul Whelan in a prisoner swap involving Russian nationals after Russia released WNBA star Brittney Griner in exchange for arms dealer Viktor Bout.

On Sunday morning, Kirby said that trading Whelan was “never a choice posed by the Russians” and that the Biden administration could only exchange Griner for Bout under the agreement. Whelan was detained in 2018 and was given a 16-year prison term.

“They treat Paul differently because of these sham espionage charges,” Kirby told Fox News on Sunday. “He is put in this special category by the Russians.”