A security expert says the four South African mercenaries, jailed for their part in a failed coup in Equatorial Guinea, are back in the country.

Nick du Toit, Jose Sundays, George Allerson and Sergio Cardoso were released on Tuesday along with Briton Simon Mann but their whereabouts since their pardon has been shrouded in secrecy.

The Institute for Security Studies’ Henri Boschoff believes the four mercenaries touched down in South Africa on Thursday night.

He said South African authorities might want to speak to the men before any official announcement is made about their return.

Neither the presidency’s office nor officials from the International Relations Department were able to confirm if the men were back.

When Eyewitness News contacted an embassy employee in Malabo, she too refused comment.

The men were supposed to fly out of the country on an Air France flight on Tuesday night but that arrangement was cancelled at the last minute.

Mann, the one behind the failed coup, returned to the United Kingdom on Wednesday.