NEW YORK — Two South Carolina prison inmates serving life sentences for murder were charged with killing four other prisoners inside a maximum-security prison, authorities said Saturday.

The accused inmates, Denver Jordan Simmons, 35, and Jacob Theophilus Philip, 25, were each charged with four counts of murder in the killings at Kirkland Correctional Institution in Columbia, the state law enforcement division said.

Authorities said Simmons and Philip lured the four men into a cell Friday morning and strangled them. An arrest warrant said one victim had also been stabbed with a sharpened broomstick. The motive for the attack is unclear.