A fence surrounds the Lee Correctional Institution on Monday, April 16, 2018, in Bishopville, South Carolina. Seven inmates were killed and 17 others seriously injured amid fighting between prisoners inside the maximum security prison in South Carolina. (Sean Rayford/AP)

This shows the Lee Correctional Institution on Monday, April 16, 2018, in Bishopville, S.C. Multiple inmates were killed and others seriously injured amid fighting between prisoners inside the maximum security prison in South Carolina. (AP Photo/Sean Rayford)

Seven inmates were killed during fights that lasted more than seven hours at a South Carolina prison Sunday night and into Monday morning, according to officials. At least six emergency agencies responded to the "mass casualty incident" at Lee Correctional Institution in Lee County that resulted in the seven inmate deaths and 17 other inmates requiring medical attention, ...

After a four day standoff with inmates holding 42 hostages, New York state police moved in to retake the prison on orders of governor Nelson Rockefeller. By the time it was over, 43 people were dead, including 10 guards and prison employees, and 33 inmates.

South Carolina authorities helped officials with the Department of Corrections and Lee County secure the prison dormitories where the incidents occurred, said Thom Berry, a spokesman for the State Law Enforcement Division (SLED), who was at the prison until early Monday morning.

COLUMBIA, S.C. -- Inmates armed with homemade knives fought each other for more than seven hours inside a maximum-security prison, leaving seven of them dead in the worst U.S. prison riot in a quarter-century, officials said. An inmate who witnessed the violence told The Associated Press that bodies were "literally stacked on top of each other."

Inmates became embroiled in "multiple inmate on inmate altercations" in three separate housing units at the Lee Correctional Institution about 7:15 p.m. Sunday, according to the state's corrections department. Officers did not secure the prison until 2:55 a.m. Monday.