Thirteen people were injured - two of them critically - when thousands of fans stormed an American football field in Stillwater, Oklahoma.
The fans took to the field in celebration after the Oklahoma State University football team's 44-10 victory over its rival, the University of Oklahoma.
Emergency official Michael Authement said fans stormed the field in the game's final seconds and people were trampled in the rush.
At least one person fell about 4.5 metres onto concrete and the two sets of goalposts were felled.
Authement said nine ambulances were called to the scene and four helicopters were deployed.
He added that 11 of the 13 injured were sent to hospital, including some with leg fractures and that two of them were treated and released.
A hospital spokesperson said they treated injuries including broken ankles, ankle sprains and back sprains.
Authement said the crowd was so big it took police at least 45 minutes to clear fans from the field. According to the university's website, the Boone Pickens Stadium has a capacity of more than 60,000.
The university and Stillwater police had no immediate comment.
APTN