WASHINGTON (AP) — The U.S. government’s top hostage negotiator defended prisoner swaps that free Americans wrongfully detained by foreign countries in exchange for the release of convicted criminals, denying on Thursday that such deals incentivize additional arrests of U.S. citizens.

“The math just is not adding up — it’s actually going down, it’s going in the other direction,” Roger Carstens, the special presidential envoy for hostage affairs, said of the population of wrongfully detained Americans.

That list has grown shorter even as the Biden administration has proved willing to make deals with adversaries, something he said suggests prisoner swaps are not encouraging nations to arrest more Americans on bogus pretenses.

“My numbers,” he added, are actually going down.”

The deals are “always hard decisions,” with the U.S. government often spending years trying to determine what the other country wants in exchange for the release of an American prisoner. The answer is generally a convicted criminal imprisoned in the U.S.

To get home WNBA star Brittney Griner from Russia, for instance, the U.S. in 2022 released arms trafficker Viktor Bout. And last December, the Biden administration freed a close ally of Venezuelan President Nicolas Maduro who was jailed on money laundering charges in exchange for the release of 10 Americans behind bars in the South American country and the return of a fugitive businessman, Leonard Glenn Francis.

“To an extent, it’s always unpalatable because the decisions are hard. But really, the alternative is those Americans don’t come home,” Carstens said.

Carstens denied that U.S. officials take into account a detainee’s celebrity status, rejecting the idea that the U.S. focused more on Griner’s case because of her popularity as a professional basketball player.

He said the 47 Americans brought home during the Biden administration reflect a broad cross-section of society.

“You will find people that are poor, rich, well-connected, not well-connected, people that are are famous, not famous, Black, white, Asian, Hispanic, Muslim, Christian, agnostic, atheist,” Carstens said. “It’s this entire array of everyone who makes up our country” he said.

The hearing was held just hours after Russian authorities said Wall Street Journal reporter Evan Gershkovich, jailed for over a year on espionage charges that the newspaper and the U.S. government have denied, will stand trial in the Ural Mountains city of Yekaterinburg.

“The bottom line is this was not unexpected,” Carstens said.

He said that while he had been hopeful about brokering a deal to get Gershkovich home before this point, the latest development “doesn’t slow or stop us down.” Carstens has also been trying to secure the release of another wrongfully detained American in Russia, corporate security executive Paul Whelan.