Cairo: Qatar’s ambassador to Egypt, Hamad Saif Bu Ainain, cancelled his flight to Sudan on Monday after a security request for him to be searched, a source at the airport said, an incident that comes amid strained ties between the two Arab countries.

“When he passed through the metal-detecting machine prior to boarding the EgyptAir plane, the machine emitted an alarm sound,” the source said. “In the beginning, the ambassador agreed to be searched. When he went through the machine more than once, the sound continued. He refused to remove his shoes, demanded his flight be cancelled and left the airport,” the source added on condition of anonymity because he was not authorised to talk to the media.

Several hours later, the diplomat returned to the airport and boarded another Khartoum-bound flight without any problem, according to the same source. The Qatari embassy in Cairo declined to comment.

Relations between Egypt and Qatar have worsened since mid-2013 when the army deposed Islamist president Mohammad Mursi, an ally of Doha, following enormous street protests against his one-year rule.

The Egyptian government and media accuse Qatar of being biased to Mursi’s Muslim Brotherhood and sheltering several Islamists wanted allegedly for inciting violence.

Earlier this year, Cairo recalled its envoy from Doha in a sign of displeasure with Qatar’s policy.

Last month, Egypt accepted a Saudi initiative to reconcile with Qatar amid scepticism that Qatar will stop its backing to the Brotherhood already designated by Egypt and Saudi Arabia as a terrorist organisation.