Former president Jiang Zemin, who served as head of state from 1993 to 2003 during which China saw huge economic and social changes, has died at the age of 96.

According to an announcement made by the Central Committee of the Communist Party and other state organs, Jiang died of leukaemia and multiple organ failure in Shanghai at 12.13pm on Wednesday.

A letter addressing the party, the military and the Chinese people described him as "an outstanding leader enjoying high prestige acknowledged by the whole Party, the entire military and the Chinese people of all ethnic groups, a great Marxist, a great proletarian revolutionary, statesman, military strategist and diplomat, a long-tested communist fighter, and an outstanding leader of the great cause of socialism with Chinese characteristics", according to Xinhua News Agency.

Jiang was born in 1926 in Yangzhou city, in Jiangsu province.

At the age of 17, he became involved in the student movement led by underground Communist Party organisations, before joining the party three years later.

After graduating with a degree in electrical engineering from Jiaotong University, he worked in a variety of industries -- from food factories to automobile plants -- before he took up government posts.

He became the mayor of Shanghai in 1985, and also served as deputy secretary and secretary of the Shanghai municipal Party committee.

In the aftermath of the student protests of 1989, Jiang was appointed general secretary of the Communist Party, replacing Zhao Ziyang, before taking over as the chairman of the Central Military Commission several months later.

As the head of the "third generation" of Chinese leaders, Jiang became president in 1993.

He continued efforts to further open up China’s economy, oversaw the return of Hong Kong to the motherland and improved the country’s relations with the international community.

His political philosophy, known as the "Three Represents", was enshrined in the party constitution in 2002. The theory characterises the Communist Party as representing advanced productive forces, advanced culture, and the fundamental interests of the vast majority of the people.

Many in Hong Kong will remember him for a famous exchange with local journalists in Beijing in 2000, when reporters were pressing him about his support for a second term as chief executive for Tung Chee-hwa.

Jiang retorted that their questions were "too simple, sometimes naive".

In 2002, he retired from the party's Politburo Standing Committee to make way for the next generation of leaders headed by Hu Jintao.

Jiang stepped down from the presidency a year later but remained chairman of the Central Military Commission, his last official post, before he gave that up as well.

Following his retirement, there have often been unverified rumours that he was suffering from ill health, including a false report by Hong Kong media of his death in 2011. But time and again, he would make sporadic public appearances to put paid to those rumours.

Many observers, though, noted his absence at the 20th National Party Congress in the capital in October, though an undated photo had been circulating around that time showing Jiang and his wife sitting by some flowers labelled as having been sent by President Xi Jinping and Premier Li Keqiang.