Brother of Russia detainee Paul Whelan calls on US to be 'more assertive' after Griner trade

The brother of a former Marine currently detained in Russia urged the U.S. to be "more assertive" after the Biden administration secured a prisoner swap with the Kremlin, trading WNBA star Brittney Griner for prolific Russian arms dealer Viktor Bout.

David Whelan told Fox News Thursday he trusts the Biden administration did its best to secure the best deal they could in getting Griner back to the states, but lamented that his brother Paul remains in Russian custody.

When asked by "The Story" anchor Martha MacCallum if he believes the White House must be more aggressive, Whelan responded the operative word should be "assertive."

"I think that the US government is a little bit behind the rogue nations who are taking Americans hostage. And the Biden administration has done a good job in the last few years of trying to get ahead of that curve," he said.

KIRK CAMERON SPEAKS OUT AFTER FAITH-BASED BOOK ‘BANNED’

"And so we need them to take the next step, which is that when they have someone like Paul -- who is a wrongful detainee in a country like Russia -- that they have a plan for how they will get a concession or how they will be prepared in order to have those negotiations and bring the person home faster than they're currently doing with someone like Paul who's been there for years."

Paul Whelan has been in Kremlin custody since 2018 when he was sentenced to 16 years in prison on espionage charges. Griner had been detained since February after authorities discovered vape cartridges containing a small amount of cannabis oil in her luggage.

David Whelan told Fox News there are plenty of Russian nationals in custody and that the Justice Department has engaged in extradition of Russians from other Western nations in the past.

He pointed to the fact Bout – nicknamed "The Merchant of Death" – had been captured in Thailand and brought to the United States, rather than having been arrested stateside.

PHILADELPHIA VIOLENCE IS ‘OFF THE CHAIN’ SAYS LEAD AGENT HIRED TO PROTECT LOCAL GAS STATION

"I think the US government can be more proactive at looking at who those people are and bringing them into custody, bringing them to justice," he said. "And of course, stopping short of turning into our enemy -- we don't want to do what these hostage-taking nations are doing. But we do, I think, need to have a plan for how we are going to respond when an American is taken as a hostage."

President Biden defended the Bout-Griner trade, saying the Kremlin is treating Whelan's case differently for "illegitimate reasons" and pointed to the return of another former U.S. Marine, Trevor Reed, from Russia earlier this year.

When asked about reports his brother had been temporarily moved out of contact with his family and to a hospital facility, Whelan said the Wagner Group – a private Russian mercenary force with alleged connections to President Vladimir Putin – had been "recruiting" in the prison where Paul was being held.

Whelan said he believed the Russian authorities didn't want the American prisoner witnessing the Wagner Group's reported activities onsite. 

CLICK TO GET THE FOX NEWS APP

In the early months of the Russian invasion of Ukraine, the Wagner Group was accused of sending hundreds of mercenaries to Kyiv with the mission to assassinate Ukrainian President Volodymyr Zelenskyy.

Despite his brother still being held by Russian authorities, David Whelan still has faith in President Biden.

"I trust the president," Whelan concluded. "I think that Mr. Bout is a person who spent a long time in U.S. custody. He's older, and that's really all I know about him."

If Biden was willing to make the current trade decision based on federal experts' advisement, "thats good enough for me," he added.

Fox News' Anders Hagstrom contributed to this report.