(Washington, DC) -- Russia has still not responded to a U.S. offer for a prisoner exchange involving Americans Brittney Griner and Paul Whelan. So said National Security Council spokesman John Kirby during a White House briefing. Kirby said President Biden remains fully committed to getting the Americans out of Russian prison cells. His comments came ahead of private meetings between the President, Griner's wife and Whelan's sister. Griner is a WNBA star and Whelan is a former U.S. Marine.