Police in Australia were forced to cancel a concert by Canadian heartthrob Justin Bieber early Monday after thousands of screaming teenage fans rushed the stage before the event was set to start, leaving several of them injured.

Justin Bieber was scheduled to sing three songs on a local breakfast show called Network Seven's Sunrise Monday morning from a concert venue at the Sydney Harbour.

Around 7 a.m. local time, about 5,000 fans surged through barricades towards the stage, according to local freelance journalist Tim Stackpool.

At least 10 girls fainted and eight were sent to hospital for hyperventilation. One of them also suffered a fractured knee.

"With the constant screaming that went on, some of these girls had difficulty catching their breath, and for that reason they passed out in the crowd," Stackpool told Â鶹´«Ã½ Channel in a telephone interview from Sydney.

Both local police and the television station said they were prepared for a large crowd, but the fans quickly worked themselves into a frenzy.

"We were expecting this to be the biggest concert we ever had, but we just couldn't have foreseen this scale," said Grant Denyer, the weather presenter for the morning program.

According to Stackpool, police told the concert's producers and Bieber's management team that the situation had grown too dangerous for the concert to go on.

"They wouldn't listen to our directions, so hence they left us with no option," Deputy Commissioner Dave Owens told reporters.

Organizers told the crowd Bieber would perform at the television station, which sent thousands of fans trekking through the streets of Sydney on the four-kilometre walk to the studio.

"Amazingly it was a public holiday in Australia today and for that reason I think the whole cavalcade of those fans went down to the TV studio and didn't strike any traffic or any morning commuters," Stackpool said. "We can be thankful for that."

Bieber performed one song live at the studio and later apologized to his fans for the cancellation.

Bieber took to his Twitter feed to say he was "just as disappointed as everyone else" that the concert was cancelled.

"I woke up this morning to the police cancelling the show for safety reasons," Bieber wrote. "I love my fans… I love it here in Australia… and I want to sing."

According to Stackpool, fans began camping out overnight and there were 3,000 of them at the venue by 3 a.m. Bieber was scheduled to perform at 8 a.m.

"The doors were meant to open at five, but they opened at three for some reason and everyone bolted," said 14-year-old Monica Caruana, who added that her friend was "knocked out" in the stampede.

While security was set up in much the same way it was for concerts at the same venue by U2, Pink and the Pussycat Dolls, the security supervisor said police were concerned about how to handle such a young group of fans.

"He said one of the difficulties was you've got fans who were not quite rioting but hysterical, but they're only 12, 13, 14 years of age," Stackpool said. "How does the riot squad deal with them?"

With files from The Associated Press