Police say four gunmen intercepted a van and a microbus carrying seven U.S. citizens, one Canadian and 10 Brazilians working for a company that provides services to Brazil's state-run oil company Petrobras.
A police spokeswoman said the two vehicles were stopped Thursday morning in Rio as they were heading to the airport. She spoke on condition of anonymity because she is not authorized to discuss the matter with the news media.
She says the assailants did not enter the van carrying the foreigners, but robbed the 10 Brazilians on the bus.
The Canadian suffered minor bruises on the forehead when the van came to a sudden stop behind the bus. No one else was hurt.
The names of the foreigners and their hometowns were not immediately available.