By Steve Kingstone BBC correspondent in Sao Paulo

The men had encroached on an Indian reservation and it is thought they were killed by indigenous people.

The area - deep in the jungle and close to the border with Bolivia - is believed to hold South America's largest diamond reserves.

Under Brazilian law, mining in Indian reservations is not permitted but that does not stop many prospectors.

The bodies were found by members of Funai, the government agency responsible for indigenous affairs.

Its team discovered the remains of 26 diamond miners - three other bodies were recovered a week ago.

The grim find appears to confirms reports of a violent attack on miners by local Indians.

Fortune seekers

About 1,000 indigenous people live in the area, which has been officially designated an Indian reservation.

Mining is illegal but that has not stopped hundreds of poor Brazilians travelling to the region hoping to make their fortune from diamonds.

Some make deals with Indian chiefs; those who do not run the risk of a confrontation.

The state governor of Rondonia says the solution lies either in improved security or the legalisation of diamond mining.

The government is considering that idea. In the meantime, a team of police officers has been sent into the jungle to recover the bodies.