(FILES) In this file photo taken on October 27, 2020 Seif Sharif Hamad, the leader of the opposition, gives a press conference…
FILE - Seif Sharif Hamad, the leader of the opposition, gives a press conference at The Alliance for Change and Transparency (ACT) head office in Stone Town, Zanzibar, Oct. 27, 2020.

DODOMA, TANZANIA - The first vice president of Tanzania's Zanzibar Island, Seif Sharif Hamad, died Wednesday morning, weeks after being hospitalized with COVID-19.

Announcing the death Wednesday, Zanzibar's President Hussein Mwinyi said he had learned with great sadness of the passing of Hamad, a prominent politician who was also the chairman of the Alliance for Change and Transparency party. 

FILE - Then-candidate Hussein Mwinyi speaks at the Jamhuri stadium in Dodoma, Tanzania, Aug. 29, 2020.

"On behalf of the people of Zanzibar, I take this opportunity to pass my condolences to the family, relatives, Alliance for Change and Transparency party, and to all the people of Zanzibar and ask them to stay calm during this mourning period," Mwinyi said.

Mwinyi declared seven days of a national mourning and said flags will be flown at half-staff. 

The cause of death has not been made public, but on January 31, Hamad was hospitalized in the archipelago after testing positive for COVID-19.

He became the first person to declare his COVID-19 status in Tanzania since April 29, 2020, as authorities dismissed the idea the virus was present in the country.

FILE - Tanzanian President John Magufuli gestures during an election rally in Dar es Salaam, Oct. 23, 2015.

On a Twitter post, Tanzania's President John Magufuli sent his condolences to Zanzibar's president and the people of Zanzibar, saying he was saddened by Hamad's passing. He did not mention a cause of death.

"I have received with profound shock the news of the death of Hon. Maalim Seif Sharif Hamad, the first vice president of Zanzibar," he tweeted. 

Hamad was challenging Mwinyi in the October polls in the election that the opposition claims was full of fraud. In December, Hamad was sworn in as the first vice president of Zanzibar as part of a unity government.