A Belgian prosecutor has denied local media reports that the murder of a security guard at a Belgian nuclear site was related to a possible terrorist threat, AFP reported on Saturday.

The prosecutor's office in charge of the case in the city of Charleroi had also denied media reports that the security pass of the murdered man had been taken away from him, the French news agency said, citing a report of Belgium’s Belga news agency.

Didier Prospero, who worked for the G4S security firm, was found shot dead in his bathroom by his three children when they returned from school on Thursday, according to AFP.

AFP also said that there had been no immediate independent confirmation from the prosecutor's office in Charleroi.

Belgian newspaper Derniere Heure (DH) reported earlier on Saturday that a security officer at a Belgian nuclear power plant has been found murdered with his work pass stolen – a disturbing development in the light of recent terror attacks in Brussels.

The man was in charge of security at a nuclear research centre in Belgium, according to AFP. Earlier media reports had said that he worked at a nuclear power plant.

A Belgian police spokeswoman has told Reuters that she could not comment because an investigation was ongoing.