Rio de Janeiro (AFP) - An attack on a media bus at the Olympic Games was by stone-throwing vandals, the Rio 2016 security chief said Wednesday, but an eyewitness insisted it was "clearly bullets".
Security director Luiz Fernando Correa said: "Stones were thrown and hit the metal part of the windows of the bus" and promised to beef up security patrols, calling it an act of vandalism by teenagers.
Three people suffered minor injuries as windows were hit by projectiles when the bus passed Rio's Curicica district, neighbouring the notorious City of God favela, late on Tuesday.
Rio 2016 spokesman Mario Andrada said preliminary forensic analysis had shown a rock was used in the attack, on what was an official media transport bus.
"The first finding of the forensic study confirms the bus was hit by a rock which is also worrying and intolerable," Andrada said.
"The complete findings of the forensic team will be made available later today."
But the findings were disputed by eyewitness Lee Michaelson, a basketball journalist who was on the bus and insisted she heard the "Pop, pop" of gunfire.
"Very close in succession, pop pop, you could hear the report of a weapon in addition to the impact on the glass," she told reporters.
Michaelson, a former airforce captain and lawyer with experience of firearms cases, said it was unlikely that stones could have hit two windows of the fast-moving bus at about the same height.
- 'Olympic-level rock-throwing' -
It is the Games' second major security scare after a stray bullet ripped through a media tent at the equestrian venue in Deodoro.
"We were moving at highway speed down the new highway when I heard two shots ring out. We'll have to wait until I see the ballistics and forensics report... before I believe this was any kind of Olympic-level rock-throwing by local teenagers," Michaelson said.
"Come on now. Two points of impact, pop pop, that quickly, the bus moving a good 45-50mph or better down a highway, to hit it at exactly shoulder to head level in the windows?" added Michaelson.
"They should add that to the Olympic Games."
Michaelson said the bus's eight-12 passengers hit the deck as the driver slowed to a halt -- before they shouted at him to keep going.
She said one passenger was in tears and there was no first aid for the injured, including a Turkish Games volunteer whose bleeding arm she treated using her water bottle and tissues.
Correa defended security along the bus route and Games spokesman Mario Andrade insisted that organisers could guarantee journalists' safety.
But Michaelson, whose 19-year-old daughter is with her at the Games, was unconvinced by organisers' immediate response to the emergency, as well as their explanation.
"My father used to say, 'Don't piss in my ear and tell me it's raining.' Come on!" she said.