The presence of armed police in the slums has not stopped killings

There have been no reports as to the fate of 12 other people travelling in the group when the killers stopped their van near a Rio de Janeiro slum.

After killing the six, the gunmen forced the driver of the van to take the bodies back to their home town Macae, 200 kilometres (125 miles) away.

They escorted the vehicle in a car and on two motorbikes for the first 100 km.

The driver told the government news service that he had set out from Macae to ferry his young passengers to a dance party in the Rio shantytown of Sao Carlos.

However, they got lost and ended up outside the city's Mineira slum, which is notorious for its gang-related violence.

Three gunmen stopped the vehicle, believing the occupants were from a rival gang and took them into the slum, where six were shot dead.

There is still no word of the missing 12.