The family of an unarmed black teenager who was killed by police in the US state of Missouri are speaking out in the wake of a preliminary autopsy report.

It finds that Michael Brown (18) was shot six times - twice in the head.

The killing nine days ago has sparked protests, with eyewitness reports of police officers with no visible ID using tear gas and rubber bullets on demonstrators.

The governor of Missouri has also called in the National Guard as protests continue in Ferguson.

Governor Jay Nixon says the troops will "restore peace and order" to the area after days of protests.

The news came as another five-hour curfew was put in place in Ferguson to try and deal with the unrest that has affected the city for over a week.

The curfew started at midnight local time (6am Irish time), and followed a similar curfew imposed on Saturday night and early Sunday morning.

The protests have now lasted for more than a week. Police say Mr Brown was a suspect in a convenience store robbery.

Eyewitnesses have said the teenager, who was unarmed, had his arms raised when he was shot dead by an officer. Police authorities have disputed this account.

They say there was a struggle and the officer suffered facial injuries.

The Brown family lawyer Benjamin Crump has been speaking at a press conference.

Medical examiner Michael Baden said he had assured the family that Michael was not in pain when he died.

Originally published 6:40am