San Francisco Mayor Edwin M. Lee died unexpectedly early Tuesday morning at the age of 65.

SF Gate reported Lee suffered a heart attack around 10:30 p.m. Monday at the Safeway on Monterey Boulevard near his Glen Park home and was taken by ambulance to San Francisco General Hospital. He passed at 1:11 a.m. Tuesday morning.

Lee was the City’s first Asian-American Mayor and presided over San Francisco’s rise to the technological forefront. As a young lawyer, Lee worked as a civil rights attorney and dedicated his career to representing low-income tenants in San Francisco. In 2011, he was elected into office after serving the remainder of former Mayor Gavin Newsom’s term after Newsom’s resignation.

While Lee had been an important public figure for San Francisco’s Chinese American community for decades, he garnered national prominence over the past year for his controversial stronghold position on the City’s sanctuary status.

His predecessor Newsom called Lee a “dedicated public servant whose intellect, integrity, boundless optimism & contagious love elevated our City” in a tweet earlier this morning, and his office released a statement that expanded on his regards for Lee.

Effective immediately, President London Breed is the Acting Mayor –– in accordance with the City Charter Board of Supervisors.

Flags at city hall were flying at half staff and Breed offered a brief statement outside the hospital. “Our thoughts and prayers are with his wife Anita, his two daughters, Brianna and Tania, and his entire family,” she said.