JOHANNESBURG (Reuters) - A video of South African police dragging a man for hundreds of meters from the back of a pick-up truck drew a storm of protest on Thursday against a force accused of routine brutality against citizens.

The man, a 27-year-old Mozambican taxi driver who had resisted arrest, died in detention of head injuries and internal bleeding, according to an initial post mortem report.

The incident was videotaped on Tuesday and was broadcast nationwide on Thursday. It soon dominated the agenda on talk shows and in social media.

"How much longer must South Africans live in fear of the very people who are supposed to protect them?" the opposition Democratic Alliance said in a statement.

"Are policemen/women generally programmed to be heartless, brutal machines?" asked citizen Patience Salane on Twitter.

Police commissioner Riah Phiyega said she was looking at the matter "in a very serious light and it is strongly condemned".

Police told media they detained the taxi driver after he parked illegally, creating a traffic jam, and then resisted arrest.

The video shows the man scuffling with police, who subdue him. He is then bound to the back of the pick-up by his arms before the vehicle drives off in front of scores of witnesses in the east Johannesburg area of Daveyton.

"The video presents a version which is different from the officers and we will have to verify it," said Moses Dlamini, the spokesman for the government's agency that investigates suspected police brutality.

Nearly 1,000 people die each year in South Africa in police custody, according to the country's police watchdog.

Successive cases of violent and unprofessional behavior by police in recent years have drawn indignation from the public.

Police shot dead 34 striking workers at a platinum mine in August last year - the deadliest security incident since apartheid ended in 1994. Post mortem reports said more than a dozen of the victims were shot in the back and separate evidence suggested police had planted weapons on dead victims.

With South Africa the focus of global attention last week when track star Oscar Pistorius was accused of murdering his girlfriend, the lead detective was removed from the investigation when it emerged he was facing seven attempted murder charges for opening fire on a minibus full of passengers.

(Reporting by Peroshni Govender; Writing by Jon Herskovitz; Editing by Tom Pfeiffer)