Three Egyptian Coptic monks were killed in a "criminal assault" inside a Coptic monastery in South Africa, the Christian Coptic Orthodox Church of Egypt said on Tuesday, and South African police said they were investigating a triple murder, Paralel.Az reports citing Reuters.

"Three monks were subjected to a criminal assault inside our Coptic monastery," the spokesman for the Coptic Orthodox Church said in statement posted on Facebook, without elaborating.

A South African police spokesperson said that authorities were investigating the murder of three priests at a church in Cullinan, a town near Pretoria.

All three victims were found with stab wounds while a fourth who survived alleged that he was hit by an iron rod before fleeing and hiding, said police spokesperson Colonel Dimakatso Nevhuhulwi in a statement.

"The motive (for the) murders is unknown at this stage," he said, adding that the suspects "reportedly left the scene without taking any valuable item(s)".