Itzik Colangi and Amir Menashe confronted the bomber when he moved their bags in order to try and place his bomb deeper inside the luggage compartment of the tour bus, packed with holidaymakers heading for the Black Sea's "Sunny Beach" resort.

The authorities have confirmed that the bomber, who was killed in the Burgas airport attack that took the lives of five Israeli tourists and a Bulgarian, was backed up by an organised group who helped him plan and carry out the attack.

Gilat Colangi, Itzik's wife, told police that as the argument escalated the bomber's controller triggered the device, an account that is borne out by other witnesses of the attack.

"An operator activated the load by remote control," she told Channel Two television in Israel.

"He [the bomber] came over to the bus, pushed their bags aside and put his own bag down. They started to argue with him – and that's when his operator, who saw them from a distance – activated the explosive."

The Burgas-based news website Besove has reported that forensic analysis of the bomber's head shows he may have been mentally disabled and used as a dispensable bomb "mule" by terrorist associates.

Other local press have reported that alleged suicide bomber has arrived from Belgium and could be a Belgian national.