Two windows have been shattered when rocks, or possibly gunfire, hit a bus carrying journalists at the Rio de Janeiro Olympics. There were no injures.

Rio organizing committee spokesman Mario Andrada says "we don't know yet if the bus was shot, or it was a stone."

Andrada says three of the 12 journalists on the bus on Tuesday suffered minor injuries. Photos showed two shattered windows, with tiny chards of glass remaining in place.

A witness on the bus said the occupants hit the floor when they heard a "popping noice."

The bus was traveling from the northern venue cluster of Deodoro to the main Olympic Park in the western suburb of Barra da Tijuca.