San Francisco Mayor Ed Lee died early Tuesday, city officials and a hospital spokesman told HuffPost.

He was 65. His cause of death was not immediately released but former San Francisco Mayor Willie Brown told local media that Lee had a cardiac arrest. 

“It is with profound sadness and terrible grief that we confirm that Mayor Edwin M. Lee passed away on Tuesday, December 12 at 1:11 a.m. at Zuckerberg San Francisco General Hospital,” city officials said in a statement. “Family, friends and colleagues were at his side. Our thoughts and prayers are with his wife Anita, his two daughters, Brianna and Tania, and his family.”

Board of Supervisors President London Breed will become acting mayor, effective immediately.

The child of Chinese immigrants, Lee was born and raised in Seattle and moved to the Bay Area to attend law school at the University of California, Berkeley. As a student, he became involved in advocacy by working for the civil rights group the Asian Law Caucus.

Lee began working for San Francisco in 1989 as an adviser to then-Mayor Art Agnos. He held various positions within the city government until he was appointed city administrator in 2005. In 2011, when then-Mayor Gavin Newsom was elected California’s lieutenant governor, the San Francisco Board of Supervisors appointed Lee as the city’s new leader. He won re-election in 2015.

The city’s first Asian-American mayor, Lee was best known for his progressive policies on immigration ― defending San Francisco as a sanctuary city ― and his support of a higher minimum wage. He also tried to combat the city’s longstanding homelessness problem with the creation of Navigation Centers, a short-term housing option, and investments in affordable housing programs. 

But his term has not been without controversy. Lee has been criticized for poorly managing the city’s growth, which has resulted in higher housing prices, congestion and traffic issues as well as social tensions due to rising income disparity. 

Willa Frej contributed reporting.