Security is being stepped up after a coach carrying journalists between Olympic venues in Rio came under attack last night.
Some reports said it was shot at, but others said stones had been thrown.
Two windows were smashed as the bus travelled between the Deodoro zone and the main transport mall in Rio's Olympic Park at around 7.30pm local time last night with about a dozen media on board.
Sherryl Michaelson, a reporter on women's basketball who is also a retired US Air Force captain, was travelling on the bus at the time.
She said: “I know what a gun sounds like. There was a very distinctive sound of the report of a gun. It was the sound before I ever saw the glass or anything.
"With my background and training, I got down on the floor as much as I could and I hollered to the others to get down.
"The others were just beginning to respond. I started yelling at them, 'Get down, get down, we are taking fire'."
A statement from the Rio Olympic Games organising committee did not confirm if the bus had been shot and said an investigation into the incident was under way.
