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The 77-year-old statesman was diagnosed with leukaemia in August 1998 and was being treated in a London hospital.

The man who led Tanzania to independence and served as its first president from 1961 to 1985, had what was described as a massive stroke earlier this week and doctors said he would not recover.

Addressing the nation on television, Tanzania's current President Benjamin Mkapa announced that he died at 0730gmt at St Thomas's Hospital in London.

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"I know it is shocking news to all of us Tanzanians who loved and revered Nyerere, the father of our nation.

"I am asking you my fellow countrymen to remain calm at this difficult time of extreme grief," he said.

He said the challenge now was for Tanzanians to build on the important foundation which he laid for our nation.

Listen to the announcement of Julius Nyerere's death (in Swahili)

An important opponent of colonialism and apartheid, Dr Nyerer stood out as an African leader who ignored the trappings of power.

However, as an African socialist his policy of "ujama", community-based farming collectives, proved disastrous for many and Tanzania's economy suffered.

Listen to the announcement of Julius Nyerere's death (in Swahili)

He helped found the Organisation for African Unity.

After stepping down as president, Dr Nyerere became an influential figure on the international scene.

Most recently he had been mediating talks in northern Tanzania aimed at ending the ethnic and political conflict in Burundi.