Jakarta – Four people were killed and 27 injured when police opened fire Wednesday morning on protesting coffee growers in the island of Flores, East Nusa Tenggara, a doctor said.

The victims were brought to hospital at Ruteng after staging a protest outside a police station in the town, hospital doctor Dupe Nababan told AFP by phone.

Provincial police chief Edward Aritonang said three people were killed. He said police first fired warning shots after the crowd broke windows at the police station.

Aritonang, quoted by Antara news agency, said the mob became increasingly unruly despite the warning shots and police began shooting at their legs.

"But maybe some of the shots went off their mark and three people died on the spot, eight others were seriously injured by gunshots and 17 others were slightly injured," he said.

Maximus Modo, a witness speaking to ElShinta radio, said some 500 men from Pocoranaka district had protested outside the police station after the arrest of seven of their colleagues on Tuesday.

Modo said the seven were detained after they tried to re-enter an area in Pocoranaka which had been declared off-limits by local authorities.

The area, formerly a forest, had been illegally cleared by farmers to plant coffee. Authorities recently moved onto the land and cut down the coffee bushes.