Tanzanian police have arrested prominent politician Tundu Lissu and four other opposition officials.

The Chadema party said three politicians, including Lissu, were detained on Sunday in the south-western town of Mbeya, on the eve of their planned rally to mark the World Youth Day.

The party’s chairman Freeman Mbowe and the head of its youth wing John Pambalu.were arrested on Monday afternoon.

The reported arrests come a year after President Samia Hassan lifted a ban on opposition gatherings and promised to restore competitive politics. Chadema has said that it did not know where its three detained leaders were being held.

The police have not officially spoken about the arrests.