Tanzanian opposition figure Tundu Lissu said he was suing the government and the telecommunications firm Tigo over a 2017 assassination attempt.

The legal action follows revelations this week that Tigo had passed on Lissu's mobile phone data to the authorities in the weeks leading up to the botched hit seven years ago.

Gunmen riddled Lissu's car with bullets at his home in the capital Dodoma on September 7, 2017.

Hit 16 times, the fierce critic of the authoritarian president at the time, John Magufuli, was evacuated to Kenya and then Europe where he received treatment.

British newspaper The Guardian reported that an internal investigator from Tigo's then-owners Millicom had testified in court that the firm was handing over Lissu's mobile phone data to the government in the weeks leading up to the hit.

Meanwhile, the investigator, former policeman Michael Clifford, is challenging his 2019 dismissal by Millicom at a London tribunal, arguing he was sacked for raising concerns about the affair.

A critic of the ruling Chama Cha Mapinduzi party, in power since Tanzania gained independence in 1961, Lissu has been arrested several times in the past.

The 56-year-old returned to Tanzania in 2023 after the government lifted a ban on opposition rallies, as he had spent the previous five years largely in exile in Belgium, returning only briefly to run for the presidency in 2020.

As the second-in-command of the main opposition Chadema party, Lissu is now challenging the policies of President Samia Suluhu Hassan, who succeeded Magufuli after his death in March 2021.