Retired Supreme Court Associate Justice Sandra Day O'Connor, the first woman to sit on the nation's high court, has died, the Supreme Court announced. She was 93.

O'Connor died Friday morning in Phoenix, Arizona, of complications related to advanced dementia, probably Alzheimer's, and a respiratory illness, the Supreme Court said in a statement.

In a statement, Chief Justice John G. Roberts, Jr. praised O'Connor as a history-making justice with a fierce independent streak. 

"A daughter of the American Southwest, Sandra Day O’Connor blazed an historic trail as our Nation’s first female Justice. She met that challenge with undaunted determination, indisputable ability, and engaging candor," Roberts said. 

"We at the Supreme Court mourn the loss of a beloved colleague, a fiercely independent defender of the rule of law, and an eloquent advocate for civics education. And we celebrate her enduring legacy as a true public servant and patriot." 

This is a developing story and will be updated.