Leading civil rights activist Dorothy Height, 98, has been hospitalized in Washington, a friend of hers told CNN on Thursday.
Height worked alongside such civil rights pioneers as the Rev. Martin Luther King Jr., future U.S. Rep. John Lewis and A. Philip Randolph in the 1960s.
"Dr. Height's condition is stable but serious. She is under excellent care at the Howard University Hospital, and we remain very optimistic in regards to her recovery," said Alexis Herman, a former secretary of labor under President Bill Clinton.
Height, who turned 98 Wednesday, is chair and president emerita of the National Council of Negro Women. She was one of a handful of key African-American leaders to meet with President Barack Obama at the White House last month for a summit on race and the economy.
Height has been active in civil rights since the New Deal era, according to her biography on the National Council of Negro Women's Web site.
As a leader of the United Christian Youth Movement of North America starting in 1933, "she worked to prevent lynching, desegregate the armed forces, reform the criminal justice system and for free access to public accommodations," the site says. She was elected president of the organization in 1957 and held the post until 1998.