WORLD: Cristiano Ronaldo breaks fan's window

Cristiano Ronaldo is to be investigated by police over claims that he attacked a teenage girl fan.

The Portuguese football star, 24, apologised after being accused of flying into a rage when he spotted Sara Pardal, 17, filming him in a Lisbon street.

But he said today: "I cannot promise that if the circumstances were repeated I would not react in the same way."

The alleged attack mars Ronaldo's £80million transfer from Manchester United to Real Madrid, which was completed this morning.

Ms Pardal was said to have filmed Ronaldo in his £200,000 red Ferrari 599 GTB Fiorano at 9pm on Sunday. The winger reportedly smashed the windows of the car she was sitting in, showering the girl in shards of glass.

Portuguese newspaper Correio de Manha reported: "The victim was injured, hit by shrapnel." Ms Pardal was treated in hospital then told police about the alleged attack.

The FIFA World Player of the Year could face charges for wounding and destroying property, Portuguese media reported. A police spokeswoman would not comment.

Ronaldo was on his way to see Elton John in concert with his mother Dolores, 54, sisters Elma and Catia and friends, and said he reacted because his mother was upset at being tailed.

"This persecution caused my mother to be so disturbed and upset that I had to stop my car to try to convince them to leave us in peace," he said.

"When I'm on my own, fine, I try to swallow it and remain indifferent. But when my mother is involved, then I'm sorry but I don't let anyone harass her. I regret what I did, but when my mother is involved it is very difficult for me to keep a calm state of mind."

Ronaldo's management company said he was the "victim of a trap by paparazzi".