South African authorities say thieves in a vehicle with police markings robbed several dozen Dutch tourists who were traveling in a bus after leaving Johanneburg's main international airport.

The government issued a statement saying the robbers, including a man dressed in a police uniform and five others in civilian clothing, stopped the bus and demanded that the 36 tourists hand over their valuables. It said one tourist was injured and was taken to hospital.

South African media say the attack on the elderly tourists in northern Johannesburg happened on Sunday night.

There have been periodic reports of thieves robbing people who have driven from O.R. Tambo International Airport in Johannesburg. Authorities say they increased security and were investigating whether any airport workers may have helped the robbers.