SEVEN inmates were killed and 17 others injured after fights broke out inside a notorious maximum-security prison in the US state of South Carolina, officials said.

State Law Enforcement Division agents helped secure the Lee Correctional Institution about 3AM Monday local time (5PM AEST) after the fights began at 7:15 PM Sunday (9.15AM Monday AEST) prison spokesman Jeff Taillon said.

No officers were hurt in the violence at three housing units, he said.

The maximum-security lockup in Bishopville houses about 1,500 inmates, some of South Carolinaís most violent and longest-serving offenders.

In late March, prisoners briefly held an officer hostage after they took control of part of a dorm, The State reported.

After the incident was brought under control, the officer was evaluated by medical personnel and released. No inmates were injured.

In February, one inmate killed another at the prison.

In October 2017, an inmate was stabbed to death, and another was killed in a fight last June.

In 2015, two officers were stabbed in a fight.