The information office spokesman said the weather had been very hot and some people at the ticket outlet near the "Bird's Nest" became impatient because they had been waiting a long time. Police were brought in to cordon off areas to keep order and prevent incidents like stampedes.

But the SCMP reporter did not obey police orders and broke through a temporary barricade to take photos, he said.

"When police officers asked him to leave the temporary restricted zone, Wong didn't listen. He kicked a police officer in the groin and injured him," he said. "Wong was then taken away by police for investigation, and the injured officer was sent to a nearby hospital."

During the investigation, Wong acknowledged he had not listened to police and had kicked the officer, the spokesman said.

"Zhang suffered groin injuries and needs further observation in hospital," he said.

No further details were provided.

Thousands in Beijing had been lining up at ticket booths since Wednesday noon, eager to get an Olympic ticket.

To give more people a chance to watch the Games and prevent scalping, organizers had stipulated that only two tickets per session would be available for purchase each time.

The line extended for more than two km at the ticket booth near the "Bird's Nest."

"The Olympics finally comes to China. I cannot afford to miss the opportunity!" said a woman surnamed Wang. The 67-year-old bought two tickets, one for a diving session in the Aquatic Center, aka the "Water Cube," and the other for baseball in Wukesong venue.