Despite “all-out” efforts to revive him, he died at 10 minutes past midnight on Friday.

President Xi Jinping overtook Li as the country’s future leader.

Though he held the second highest-ranking position in China, he has been widely isolated among China’s top leaders in recent years.

He was the only incumbent top official who did not belong to Mr Xi’s loyalists.

As Ian Chong, non-resident scholar at the Carnegie China think tank, told the BBC, “Li’s death represents a loss of a prominent moderation voice within the Chinese Communist Party (CCP).

Li, who stepped down as premier in March this year, died early on Friday after suffering a sudden heart attack on Thursday.

On Chinese social media, many are mourning his passing, with many expressing shock and grief – though comments appear to have been restricted on many posts.

An anonymous user on the Chinese social media site Weibo commented, “This is too sudden, he was so young.”. A second user described him as a “pillar of our home”.

Li’s death has also been reported in state media, in which his contribution to the CCP and country is acknowledged. In the past, protests have been sparked by the deaths of former Chinese leaders. During Jiang Zemin’s death last year, there was a subtle criticism of President Xi in the outpouring of mourning.