WASHINGTON, DC. (CW44 News At 10 | CNN) — The brother of Paul Whelan, an American who has been held by Russia for alleged espionage since 2018, on Thursday applauded a proposed prisoner swap made by the Biden administration, saying it’s a “very positive” step toward securing his sibling’s release.

“It’s very positive. This is an obvious attempt by the American government to find a concession that the Russian government might want in order to allow Paul and also Ms. Griner to be released,” David Whelan told CNN’s Victor Blackwell on “Newsroom,” referring to WNBA star Brittney Griner, who has been jailed in Moscow for drug possession since February.

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“It looks like President (Joe) Biden is committed to making the difficult decisions to bringing Americans home. And I’m grateful for that,” he added.

The comments come a day after CNN’s exclusive reporting that the Biden administration — after months of internal debate — has offered to exchange convicted Russian arms trafficker Viktor Bout as part of a potential deal to secure the release of Whelan and Griner, according to people briefed on the matter. Both Americans are classified as wrongfully detained.

Secretary of State Antony Blinken announced Wednesday that the US presented a “substantial proposal” to Moscow “weeks ago” to secure the release of Whelan and Griner, but did not go into specifics about what was included in the proposal.

Kremlin spokesman Dmitry Peskov said Thursday that “so far, there is no agreement on this issue.” Later that day, State Department spokesperson Ned Price suggested that Moscow has not meaningfully engaged on the proposal.

Sources told CNN that the plan to trade Bout, a convicted Russian arms trafficker serving a 25-year US prison sentence, for Whelan and Griner received the backing of Biden after being under discussion since earlier this year. Biden’s support for the swap overrides opposition from the Department of Justice, which is generally against prisoner trades.

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David Whelan told CNN that he first heard of the offer on Wednesday, saying, “We know that there are things going on, but we aren’t necessarily involved in the details of offers that are being made or even the offers that might be contemplated.”

“We had heard things like that the Department of Justice had been opposed to doing prisoner trades. So we weren’t sure if that was a hurdle that was going to be cleared,” he added.

The Whelan and Griner families have urged the White House to secure their release, including via a prisoner exchange if necessary.

Asked how his brother is doing right now, David Whelan replied: “Not so great.” He went to say that Russian sanctions have caused the prison to cut back on food “so he’s eating less.”

“He has lost a lot of weight. We hope that he just continues to survive day to day until he’s able to come home,” he said.

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