He died on Wednesday from heart complications at a hospital in Dar es Salaam, Samia Suluhu Hassan said in an address on state television.
Tanzania's President John Magufuli has died aged 61, the country's vice-president has announced.
He died on Wednesday from heart complications at a hospital in Dar es Salaam, Samia Suluhu Hassan said in an address on state television.
Magufuli had not been seen in public for more than two weeks, and rumours circulated about his health.
Opposition politicians said last week that he had contracted Covid-19, but this has not been confirmed, BBC reports.
"It is with deep regret that I inform you that today... we lost our brave leader, the president of the Republic of Tanzania, John Pombe Magufuli," Vice-President Hassan said in the announcement.
She said there would be 14 days of national mourning and flags would fly at half-mast.
Magufuli was declared president on his 56th birthday in October 2015. He was elected for a second term following a disputed poll last year.
He was one of Africa's most prominent coronavirus sceptics and called for prayers and herbal-infused steam therapy to counter the virus.
Since May, Tanzania has not published details of its coronavirus cases, and the government has refused to purchase vaccines.
Magufuli was last seen in public on 27 February, but Prime Minister Kassim Majaliwa insisted that the president was "healthy and working hard" last week.
On Monday, police said they had arrested four people on suspicion of spreading rumours on social media that the president was ill.