Aref Ali Nayed, the head of Jordan's Royal Islamic Strategic Studies Centre, called the baptism of journalist Magdi Allam a deliberate and provocative act.

The Pope traditionally baptises adult converts to Catholicism on Easter eve.

Mr Allam's invitation to the ceremony, which took place in St Peter's Basilica, was however kept secret by the Vatican, until just before the Easter vigil mass.

In a stinging rebuke of Saturday's televised ceremony, Mr Nayed denounced what he called "the Vatican's deliberate and provocative act of baptising Allam on such a special occasion and in such a spectacular way".

"It is sad that the intimate and personal act of a religious conversion is made into a triumphalist tool for scoring points," he said in a written statement.