Eleven South African minibus taxi drivers were shot dead and four injured when unknown gunmen opened fire on their vehicle in KwaZulu Natal province, police said Sunday.

National commissioner of police Khehla Sitole said the men were travelling back to Johannesburg from a colleague’s funeral on Saturday night when they were ambushed.

“Preliminary reports indicate that that the 11 were among 17 people coming from a funeral… Four victims were critically injured and taken to hospital while two survived unscathed,” he said.

Police launched a manhunt to find those responsible.

“We will await for the investigation to advance before speculating on a motive,” said Sitole.

Private minibuses provide essential transport for millions of South Africans, but violence is common between rival taxi groups as profitable routes are hotly contested.