Police blocked access to the homes of two opposition leaders in Tanzania's commercial capital Dar es Salaam on Monday, their party said, ahead of planned protests which authorities have banned.

Police blockaded the residences of the CHADEMA party chairman Freeman Mbowe and his deputy Tundu Lissu, having said Monday's demonstration against alleged killings and abductions of opposition officials would be illegal.

The East African country's rights record has improved under President Samia Suluhu Hassan, who took office in 2021 following the death of her hardline predecessor John Magufuli.

Police abuses targeting critics of the government have continued, however, and intensified in the run-up to local government elections in December, and the national election in 2025, rights defenders say.

Earlier this month a senior CHADEMA member was abducted from a bus by armed men his body later found on the outskirts of Dar es Salaam with signs he had been beaten and acid poured on his face.

Police briefly arrested Mbowe, Lissu and hundreds of their supporters to prevent them from attending a banned party conference in the southwest of the country in August.

"Since last night and until this morning, September 23, 2024, the police force has closed all the roads leading to the home of the chairman of the national party," CHADEMA said on the social media platform X.

Lissu, who survived being shot 16 times during an assassination attempt in 2016, said that three police vehicles full of officers in riot gear were outside his house.

"They've informed me I'm directed to be taken to the Regional Crimes Officer," he wrote on X. "I'm getting ready to go."

Over the weekend Dar es Salaam police chief Jumanne Muliro said Monday's protest would breach the peace and that his officers would take tough legal action to prevent it from taking place.