(WASHINGTON) -- Cherelle Griner said the letter President Joe Biden wrote in response to her wife, WNBA star Brittney Griner, amid her detention in Russia brought both of them "so much joy."
"I believe every word that she said to him, he understood and he sees her as a person," Cherelle Griner said at a press conference in Chicago on Friday afternoon. "And he has not forgotten her, which was her biggest cry in her letter."
Griner, who plays for the Phoenix Mercury, personally reached out to Biden in a handwritten letter that the White House received on Monday, urging the president to help her get out of Russia where she has been detained for more than four and a half months.
"As I sit here in a Russian prison, alone with my thoughts and without the protection of my wife, family, friends, Olympic jersey or any accomplishments, I'm terrified I might be here forever," Brittney Griner wrote to the president.
Secretary of State Antony Blinken said in a tweet on Thursday that the U.S. officials who attended the second day of Griner's trial in Russia on Thursday delivered Biden's letter to Brittney Griner.
White House press secretary Karine Jean-Pierre told ABC News on Thursday that the president was “deeply moved” by Griner’s letter, but wouldn’t say what the president wrote in his response.
"I'm grateful and I'm thankful that the administration that was the first one that BG ever voted for, took the time to see her as a person," Cherelle Griner continued, "to see her in the midst of what she's going through and to speak to me directly and let her know that they are exhausting all efforts to bring her home."
Griner, a two-time Olympic gold medalist, was visiting Russia to play basketball in the off-season when she was detained at Sheremetyevo International Airport on Feb. 17 after being accused of having vape cartridges containing hashish oil, which is illegal in the country.
The U.S. government classified Griner's case on May 3 as "wrongfully detained," meaning the U.S. will more aggressively work to negotiate her release even as the legal case against her plays out, the State Department has said.
Biden and Vice President Kamala Harris called Cherelle Griner to discuss efforts to release the WNBA star, the White House said in a statement on Wednesday.
"The president called Cherelle to reassure her that he is working to secure Brittney's release as soon as possible, as well as the release of Paul Whelan and other U.S. nationals who are wrongfully detained or held hostage in Russia and around the world," the White House said in the statement.
Cherelle Griner was joined at the press conference by Rev. Al Sharpton, founder and president of the National Action Network and leaders from the WNBA, including Nneka Ogwumike, Los Angeles Sparks power forward and President of the WNBA Players Association and WNBA Players Association Executive Director Terri Jackson.
Sharpton called for Biden and Blinken to arrange a trip for faith leaders to see Griner in prison as part of a prayer visit.
"After speaking with her wife last week, I am deeply concerned for Brittney Griner's physical, mental, and spiritual wellbeing," Sharpton said in a statement on Tuesday.
Cherelle Griner thanked Sharpton for his support and thanked the WNBA for honoring and supporting her wife throughout her detention, including compensating her salary and bringing attention to her case on and off the court.
"It has just been overwhelming for my entire family -- the joy of knowing that BG's footprint was so big -- that even in her absence, you still can't miss her," Cherelle Griner said.
Along with advocates, leaders and players in both the WNBA and the NBA have called for Griner's release and raised awareness about her case.
The WNBA, which kicked off its 2022 season on May 6, is honoring Griner with a floor decal bearing her initials and jersey number (42) on the sidelines of all 12 WNBA teams.
Brittney Griner's detention was extended repeatedly, most recently through Dec. 20, which is the expected length of her trial. If convicted, Griner, 31, faces up to 10 years in prison and also has a right to an appeal.
Brittney Griner said she "would like to plead guilty" Thursday morning on drug charges in a Russian court, saying that the vape cartridges containing hashish oil were in her luggage unintentionally. She said that she had no "intention" of breaking Russian law, adding that she was is in a rush and did not mean to leave the cartridges in her bag.
Brittney Griner is expected to appear in court on July 14 for the third day of her trial.
Calls to free Brittney Griner escalated following the release of U.S. Marine veteran Trevor Reed last month, who was freed from a Russian prison as part of a prisoner exchange. Former Marine Paul Whelan has also been detained in Russia since 2019.
Reed's family met with Biden after they protested outside the White House, but despite their outreach, Whelan's family had not spoken directly with Biden until Friday. Whelan's family voiced disappointment after Biden's call with the Griner family, saying that they have not heard from the president and worry that Whelan would be forgotten.
Biden called Elizabeth Whelan, Paul Whelan's sister, on Friday to reaffirm his commitment to bringing Paul Whelan home from Russia, according to a White House official.
“President Biden reaffirmed that he is committed to bringing Paul home as soon as possible, and the U.S. government will continue its efforts to secure the release of Paul as well as Brittney Griner and all other Americans who are held hostage or wrongfully detained around the world," the White House official told ABC News. "The U.S. government will continue to be in regular contact with Paul’s family, and with the families of other Americans held hostage or wrongfully detained abroad, to provide support and assistance and keep them updated on efforts to secure the release of their loved ones.”
Asked by ABC News how the White House can assure Whelan's family that he is not forgotten, Jean-Pierre said the administration wants to "assure" the Whelan and Griner families that Biden will use "every means that we have" to bring them home.
"Clearly, we cannot negotiate in public. That is not something that we’re going to do. But, we’re committed to making sure they all get home safely," she said.
ABC News' Justin Gomez, Cindy Smith, Tanya Stukalova, Kendall Ross, Shannon Crawford and Ben Gittleson contributed to this report.