Outspoken opposition figure shot and wounded

The opposition, rights groups and Tanzania's government expressed shock and demanded a full investigation.

"The attack took place at his Dodoma residence at midday," the main opposition party CHADEMA, of which Lissu is a leading member, said in a statement, adding that the lawmaker was seriously wounded and rushed to hospital.

Party spokesman Tumaini Makene described Lissu's condition as "critical" while local media reported he had been shot in the stomach and leg.

Regional police commander Gilles Muroto said an investigation was underway.

"We are asking fellow citizens with information to help us," he said, adding that initial enquiries were focussing on a car believed to have followed Lissu to his home.

"This cowardly attack on one of Tanzania's most fearless and prominent politicians raises concerns about the safety of all dissident voices in the country, at a time when space for dissent is quickly shrinking," said Sarah Jackson of rights group Amnesty International.

"This heinous crime must not be swept under the carpet," she added.

Lissu, 49, has had a series of run-ins with the government of President John Magufuli and has been arrested at least six times this year, accused of insulting the president and disturbing public order, among other charges.

'Climate of fear'

"The authorities must take steps to reassure Tanzanians and the world that his shooting was not politically motivated," Jackson added.

In a statement, Magufuli's ruling Chama Cha Mapinduzi (CCM) party condemned "this cruel and inhuman act" and urged police to investigate fully.

Magufuli tweeted that he was "shocked to hear the news of the attack on Tundu Lissu and I pray to god almighty that he will soon recover."

Lissu serves as chief whip for the parliamentary opposition and president of Tanzania's bar association, the Tanganyika Law Society, as well as being CHADEMA's attorney general.

His most recent arrest was in August after revealing that a plane bought for the national carrier had been impounded in Canada over unpaid government debts.

Magufuli has been praised for cracking down on corruption since his election in 2015 but criticised for his authoritarian rule with opposition meetings banned and newspapers shut down, moves Lissu has loudly condemned as creating a "climate of fear".

His party said Lissu was shot just after a parliamentary session.

"CHADEMA strongly condemns this act, and we are following up closely on his situation," the party added.