Africa's youngest billionaire was kidnapped by armed men in Dar es Salaam.
Mohammed Dewji (43), who is said to have $ 1.5 billion in assets and is the president of the MeTL Group, which operates in about 10 countries in various sectors including agriculture, transportation and nutrition, was abducted when he entered the gym.
Regional Governor Paul Makonda said, "Initial information suggests that he was abducted by whites who were traveling in two vehicles, and this type of incident is new here."
Lazaro Mambosasa, police chief of Dar es Salaam, said at a news conference that the kidnappers "blew up" before packing Dewji in a car.
He said police are looking for suspects and have already made arrests.
Dewji was born in Tanzania and studied at Georgetown University in Washington DC. He served from 2005 to 2015 as a Member.
In 2013, he was the first Tanzanian on the cover of Forbes magazine and was voted "Forbes Africa Person of the Year" in 2015.
Dewji is also the principal shareholder in the Simba football club based in Dar es Salaam.
He is ranked 17th by Forbes on his list of African billionaires.
Dewji is married and has three children. In 2016, he signed a pledge to donate at least half of his assets for philanthropic purposes.