State prosecutors said the terrorism charges against Mbowe did not relate to his planned activities in Mwanza but alleged offences that occurred last year in a different part of Tanzania.
A court in Tanzania has charged the leader of the main opposition party with terrorism-related offences, following his arrest that drew international concern and criticism of the country's new president.
Chadema chairman Freeman Mbowe was detained last week along with 15 other members of the party in a late-night crackdown government critics said bore the hallmarks of the oppressive rule of country's late leader.
State prosecutor Ester Martin said Mbowe had been charged with two counts of "economic sabotage", crimes that do not allow for bail in Tanzania.
"These are terrorism financing and terrorism conspiracy," she told reporters late Monday.
Chadema said Mbowe had been charged in Kisutu court with terrorism crimes without his family or lawyers present.
The party chairman and the other Chadema officials were arrested in the Lake Victoria port city of Mwanza last Wednesday ahead of a planned public meeting to demand constitutional reform.
In a statement released on Monday, Chadema director for communications John Mrema said the opposition leader has been taken to remand.
Mrema said that Mbowe was ill and a relative who visited him early Monday informed the police that he was unwell and asked them to take him to hospital.
"Till 12 in the afternoon he was not taken to the hospital for treatment and tests," he said then.
In another statement, Chadema said that Mbowe's family and lawyers were later told he was being transferred to hospital for health checks but he was instead "taken to the court quietly" and charged without any of his legal representatives present.
Six others charged
During a search at Mbowe's home in the city, laptops and other devices were seized.
State prosecutors said the terrorism charges against Mbowe did not relate to his planned activities in Mwanza but alleged offences that occurred last year in a different part of Tanzania.
"Mbowe knew that he was being investigated for terrorism, and he left to Mwanza after knowing that he would be arrested," police spokesman David Misime said late Monday.
Six others were also being charged with the same offences, he added. The case will be mentioned next in court on August 5.
The charges come four months after Tanzania's first female President Samia Suluhu Hassan took office following the sudden death in March of John Magufuli, under whose autocratic rule such clampdowns on the opposition were frequent.
Samia had reached out to the opposition and vowed to defend democracy and basic freedoms, spurring optimism that Tanzania would be steered away from the heavy-handed and uncompromising leadership of her predecessor.
But the roundup of key Chadema figures was condemned by rights groups and opposition activists as evidence the administration's intolerance of dissent still prevailed.
The United States expressed concern over Mbowe's arrest and urged Hassan to ensure freedoms for all Tanzanians.
