The head of Rwanda's diaspora association in Mozambique was killed in an ambush on Monday, police said, raising speculation the assassination may have been politically motivated.

Three armed men ambushed and opened fire on Louis Baziga, 47, as he drove out of a shop in the Boane district of Mozambique's capital Maputo, Mozambique's police department said.

"The victim was still alive when he was taken to the provincial hospital of Maputo, but could not hold out and died," it said in a statement.

Rwanda's ambassador to Mozambique Claude Nikobisanzwe told Rwandan media the police were conducting investigations but that no suspects had so far been arrested.

The motivations for the killing remain unclear. But Baziga, who survived an assassination attempt in 2016, is believed to have been an ally of the Rwandan government and some residents suspect he was targeted by dissidents. 

"It may be for political reasons," said one Rwandan living in Maputo, who refused to be named. "We all live in fear because we know we are persecuted."

Another Maputo resident from Rwanda told AFP Baziga had been in conflict with members of his church.

"It may be this matter but it may also be a political affair," the resident said.

Rwanda President Paul Kagame's own government tactics came under international scrutiny in 2014, when the president's former spy chief Patrick Karegeya was found strangled in a luxury hotel in Johannesburg hotel on New Year's Day.

South African prosecutors said they found "close links" last between the murder suspects and Kagame's government. Rwanda has always denied the allegations.

Karegeya took charge of Rwanda's foreign intelligence services for a decade, until he fell into disgrace. He was jailed twice, in 2005 and 2006.