WASHINGTON >> President Joe Biden today reassured the wife of detained WNBA player Brittney Griner, who is on trial in Russia, that he is working to win Griner’s freedom as soon as possible, the White House said. Cherelle Griner, who has criticized the way her wife’s case has been handled, said later that she was “grateful” for the outreach but would keep up the public pressure.

Biden’s conversation with Cherelle Griner followed Brittney Griner’s personal appeal to the president in a handwritten letter from the basketball player that the White House received on Monday. Griner said in the letter that she feared she would spend forever in detention in Russia and asked Biden to not “forget about me and the other American Detainees.”

Griner has been detained in Russia for more than four months and is currently on trial, accused of possessing vape cartridges containing cannabis oil.

The call was placed as Griner’s family has become more aggressive in pressuring the Biden administration by speaking out about her case, including Brittney Griner’s letter to the president and television interviews by Cherelle Griner, in which she has said she did not think the government was doing enough to bring her wife home.

“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 a statement. “He also read her a draft of the letter the President is sending to Brittney Griner today.”

Biden’s call also followed a public plea from more than 1,100 Black women leaders in business, sports, religion, labor, media, civil rights, education, government, entertainment and technology for the administration to “make a deal to get Brittney back home swiftly and safely and to meet with Brittney’s wife Cherelle immediately.”

During the call, Biden offered Griner’s family his support and committed to making sure they receive “all possible assistance” during the administration’s pursuit of Brittney Griner’s release, the White House said.

Vice President Kamala Harris also spoke with Cherelle Griner.

“I am grateful to the both of them for the time they spent with me and for the commitment they expressed to getting BG home,” Cherelle Griner said, using her wife’s initials.

“While I will remain concerned and outspoken until she is back home, I am hopeful in knowing that the President read my wife’s letter and took the time to respond,” she continued in a statement shared on Instagram. “I know BG will be able to find comfort in knowing she has not been forgotten.”

Griner, 31, is in the midst of a trial in Russia that began last week after she was arrested on Feb. 17 on charges of possessing cannabis oil while returning to play for her Russian team. She could face 10 years in prison if convicted of large-scale transportation of drugs.

The trial was scheduled to resume Thursday. Fewer than 1% of defendants in Russian criminal cases are acquitted and, unlike in U.S. courts, acquittals can be overturned.

Cherelle Griner told “CBS Mornings” in an interview Tuesday that it was “disheartening” to her that she had yet to hear from Biden during her wife’s detention.

A representative for Cherelle Griner did not immediately respond to a text message from The Associated Press. Cherelle Griner was scheduled to speak publicly tonight at a rally in Phoenix organized by Brittney Griner’s WNBA team.

White House press secretary Karine Jean-Pierre told reporters today that Biden “has been clear about the need to see every American who is wrongfully detained or held hostage abroad released, including Brittney Griner.”

“This has been top of mind for the president,” she said. Jean-Pierre added that Biden is updated daily on the status of efforts to win freedom for Brittney Griner and other Americans the U.S. government believes are being wrongfully detained in Russia and elsewhere.

Representatives for Brittney Griner on Monday shared excerpts from her letter to the president.

In one, she wrote, “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.”

The letter was delivered to the White House on the Fourth of July, which Brittney Griner said is a special day for her family.

“On the 4th of July, our family normally honors the service of those who fought for our freedom, including my father who is a Vietnam War Veteran,” the center for the Phoenix Mercury said. “It hurts thinking about how I usually celebrate this day because freedom means something completely different to me this year.”

Griner’s supporters have encouraged a prisoner swap like one in April that brought home Marine veteran Trevor Reed in exchange for a Russian pilot convicted of drug trafficking conspiracy.

Russian news media have repeatedly speculated that she could be swapped for Russian arms trader Viktor Bout, who is serving a 25-year sentence on conviction of conspiracy to kill U.S. citizens and providing aid to a terrorist organization.

Russia has agitated for Bout’s release for years. But the wide discrepancy between Griner’s case — involving alleged possession of vape cartridges containing cannabis oil — and Bout’s global dealings in deadly weapons could make such a swap unpalatable to the U.S.

Others have suggested she could be traded along with Whelan, a former Marine and security director serving a 16-year sentence on an espionage conviction that the U.S. has repeatedly described as a setup.