STILLWATER, Okla. — Thousands of fans stormed the field and tore down goalposts after Oklahoma State’s 44-10 college football victory over archrival Oklahoma, leaving at least 13 people injured, including two in critical condition, medical authorities said early today.

Michael Authement, who heads the command post at emergency medical provider LifeNet EMS, told The Associated Press that a throng so big took to the field as the game ended that some fans were trampled and one person fell at least 15 feet onto concrete during a wild celebration by Oklahoma State fans.

No. 13 Oklahoma State routed the Sooners on Saturday night to win the Big 12 championship and make its case to play for the BCS national title. The Cowboys snapped an eight-game losing streak in the rivalry and won their first outright conference title since 1948 in the three-team Missouri Valley.

“They won the game and stormed the field and ripped down the goalposts and some were jumping off the stands and hit the field and others got trampled. It was a nasty deal,” Authement said.

He said it took police at least 45 minutes to clear fans from the field at Boone Pickens Stadium in Stillwater. “Thousands of people stormed the field. You couldn’t move there were so many people,” he added.

AP photographs showed fans climbing atop the yellow goalposts and tearing them apart amid a crush of people on the field. Scores of hands stretched out to pull down the goalposts during the celebration.

Authement said ambulances rushed 11 of the injured away and the two in critical condition were flown to Oklahoma City hospitals. He said he knew of leg fractures and that two of the 13 had minor injuries and were treated at the scene and released.

Others suffered broken ankles, ankle sprains and back sprains, said Shyla Eggers, public relations director for Stillwater Medical Center.

An Oklahoma State University police central dispatcher said she had no immediate details to release when contacted by AP and the public information officer did not immediately return messages seeking comment. Stillwater police and the Oklahoma highway patrol also had no immediate comment.