According to witnesses, Beckham was heading for the pitch at about 2:40 pm and was about to play with university students and players from Shenxin Football Club after meeting school officials.

But his walk toward the pitch was made difficult by the huge crowd. As soon as he reached the steel-fence enclosed pitch, security guards tried to shut the only gate, but failed to stop the crowds before the stampede took place.

Pictures taken by bloggers and media workers showed a police officer on the ground. She had blood on her face and was being cared of by others.

Many people stumbled amid the chaos as an officer climbed on top of the fence and yelled at the crowds to restore order. The injured were carried to safety by others or on makeshift stretchers.

"I was pushed by the crowd and fell down," an unidentified student told the Xinmin news website. "My legs were stuck, and then my chest. I could not breathe. I was almost killed."

Tongji University declined to disclose how many police officers and security guards were dispatched for the event or who should be blamed for the accident, and described the incident in a statement as "short-time congestion caused by the high spirits of people".

It put the number of the injured at six — five security workers and one overseas student.

Because of the accident, the event was canceled and Beckham arrived in Hangzhou, Zhejiang province, at 5:40 pm to continue his tour.

"I had an incredible response from everyone at Shanghai Tongji University today. Sorry I couldn't get out on the pitch to see the teams," Beckham wrote on his Sina Weibo micro blog, a popular micro-blogging website.

"It was impossible to get through the massive crowds. I heard there were a few injuries, hope the fans are OK and I wish them a speedy recovery," he added.