Seven inmates were killed and more than a dozen injured after fighting broke out at a maximum security prison in South Carolina.
Prisons spokesman Jeff Taillon announced the deaths after state police helped secure Lee Correctional Institution in the early hours of Monday.
Mr Taillon said no officers were wounded after multiple inmate fights broke out at 7:15pm on Sunday.
He said 17 of the injured required medical attention outside the prison.
The South Carolina Department of Corrections tweeted to say the fight involved multiple inmate-on-inmate altercations in three housing units.
Lee County Fire and Rescue said ambulances from multiple jurisdictions lined up outside to tend to the wounded.
The local coroner’s office also responded.
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The maximum-security facility in Bishopville houses about 1,500 inmates – some of South Carolina’s most violent and longest-serving offenders.
Two officers were stabbed in a fight in 2015. In February this year, one inmate killed another.
The deaths at Lee are the most in any South Carolina prison in recent years. Four inmates were killed by a pair of prisoners in the state’s Kirkland Correctional Institution last year.