National Security Council Coordinator John Kirby says Russia has not responded to the “substantial proposal” the US offered in July to release WNBA star Brittney Griner and former US Marine Paul Whelan. Kirby told the media during Friday’s White House press briefing that the U.S. has made a “serious offer” to negotiate the return of Griner and Whelan, but added that those discussions are “still ongoing.” . U.S. basketball player Brittney Griner, who was detained at Moscow’s Sheremetyevo Airport and later charged with illegal possession of cannabis, sits inside a defendant’s cage during the reading of the court’s verdict in Khimki, outside Moscow, August 4, 2022. (REUTERS / Evgenia Novozhenina/Pool) “They have not responded to our offer, we have made a serious offer to take Brittney Griner and Paul Whalen back home,” he said. “The Russians have not responded to this offer. But that doesn’t mean we’re not still in negotiations.” BRITNEY GREENER AND PAUL WHELAN’S FAMILIES TO MEET BIDEN AS AMERICANS REMAIN IN RUSSIAN PRISONS Kirby was pressed further on the apparent impasse, but said that if he had an answer to why the Russians didn’t respond, “we might already have a deal.” “I think that’s a better question to our Russian colleagues. We made a serious proposal. We want them to accept that, honestly, these two people should be home anyway, period. But we understand that this will probably have to be the outcome of the negotiation process, in which we are willing to engage honestly and fully, and we have. And we expect them to take the offer that’s on the table,” Kirby said. Paul Whelan, a former US Marine accused of espionage and arrested in Russia in December 2018, stands inside a defendant’s cage as he awaits his verdict in Moscow on June 15, 2020. (KIRILL KUDRYAVTSEV/AFP via Getty Images) CLICK HERE FOR MORE SPORTS COVERAGE ON FOXNEWS.COM President Biden was scheduled to meet with the Griner and Whelan families on Friday. This comes nearly two months after Foreign Secretary Antony Blinken confirmed that the Biden administration made ‘substantial proposal’ to Russia to facilitate the return of Griner and Whelan. “What I can tell you for sure is that the president is not going to give up,” Kirby said Friday. WNBA star and two-time Olympic gold medalist Brittney Griner listens to a verdict in a courtroom in Khimki, just outside Moscow, on August 4, 2022. (Evgenia Novozhenina/Pool Photo via AP) CLICK HERE TO GET THE FOX NEWS APP “He’s sure that will remain at the forefront of his and his team’s mind. And they’re going to continue to work as hard as they can. We want these two people back where they belong with their families. They should be there already.” . Griner was sentenced last month to nine years in prison after pleading guilty to drug charges. He appealed the decision, while Whelan is serving a 16-year sentence on espionage-related charges that he and his family say are false. The Associated Press contributed to this report. Paulina Dedaj is a Digital Reporter for Fox News and Fox Business. Follow Paulina Dedaj on Twitter at @PaulinaDedaj. If you have a tip, you can email Paulina at [email protected]