The Chinese Consulate General in San Francisco Tuesday expressed condolences over city Mayor Ed Lee's sudden death from a heart attack.

"The Consulate General of the People's Republic of China in San Francisco is deeply saddened by the news of Mayor Ed Lee's sudden passing" the consulate general said in a press release.

"As the first Chinese-American Mayor of San Francisco, Mayor Ed Lee made tremendous contributions to friendly exchanges and mutually beneficial cooperation between San Francisco and China," it said.

May Lee will be remembered as a great mayor and an advocate and practitioner of US-China friendship, it added.

Lee, the first Asian American mayor in the history of San Francisco in the US state of California, died unexpectedly early Tuesday morning at the age of 65.

He was elected San Francisco mayor in 2011 and won a re-election in 2015.

Lee is survived by his wife and two daughters.