At least two inmates were killed and 13 others were injured Monday during a riot at the Oklahoma State Reformatory, state officials said.

Kevin Rowland, chief investigator for the state Medical Examiner's office, confirmed the two fatalities at the medium-security facility in southwest Oklahoma, but said additional details were not immediately available.

Oklahoma Highway Patrol trooper Betsy Randolph said 15 people were stabbed. She said three had died.

The reason for the discrepancy in the number of dead was not immediately clear.
Warden's secretary Leda Reese said the situation was under control Monday afternoon.

Police said ambulances were dispatched to the prison, which is located about 15 miles northeast of Mangum.

Randolph said the prison was locked down.