Tanzanian police have arrested prominent politician Tundu Lissu and two other officials from the opposition Chadema party, the party said.
The three were said to have been arrested on Sunday in the southwestern town of Mbeya, on the eve of a demonstration they had planned to mark World Youth Day.
The reported arrests came a year after President Samia Hassan lifted a ban on opposition rallies and vowed to restore political competition.
On Sunday, police banned Chadema’s demonstration, saying it was intended to foment violence.
They cited the party’s call to unite as “youth in Kenya” have done, apparently referring to weeks of bloody anti-government demonstrations in the neighboring East African country.
A Chadema official told the BBC on Monday morning that he did not know where the arrested leaders were being held.
Police have not officially spoken about the arrests. The BBC has contacted them for comment.
Chadema spokesman John Mrema said groups of youths travelling on chartered buses were arrested and forced to return to their respective regions under armed guard.
According to the party’s youth wing, around 10,000 young people would gather in Mbeya to celebrate Youth Day, under the slogan “Take charge of your future”.
But the police said in a statement that such gatherings would not be permitted either in the city or elsewhere in the country.
Chadema officials shared photos of a large group of about 100 party members who they said were arrested in Iringa, a town near Mbeya. They were later released and escorted back to where they came from.
Chadema condemned the arrests, while party president Freeman Mbowe called in a post on X for “the immediate and unconditional release of our leaders, members and supporters arrested across the country.”
Mr Lissu, who survived an assassination attempt in 2017 after being shot 16 times, returned to Tanzania last year after two years in exile in Belgium.
He returned after President Samia lifted a ban on political gatherings imposed by former President John Magufuli in 2016.
The ban had prevented political parties from holding rallies and even engaging in internal political activities.
Ms Samia, who came to power in 2021 after Mr Magufuli’s sudden death, has been praised for moving away from many of her predecessor’s policies.
But following the arrests, some opposition politicians have criticized her, saying she is not ready for political reconciliation.
Presidential and parliamentary elections in Tanzania are expected to be held late next year.
Further reports by Basillioh Rukanga