Their presence came despite a bitter eight-month dispute
Referees from four countries boycotting Qatar attended a high-profile FIFA World Cup seminar in Doha on Monday, despite the ongoing Gulf political crisis.
Representatives from Saudi Arabia, United Arab Emirates, Bahrain and Egypt were at the opening of the referees' seminar, an almost week-long event which will help football's governing body decide on the final list of those who will officiate at this year's World Cup in Russia.
Their presence came despite a bitter eight-month dispute which has seen Qatar, the 2022 World Cup hosts, isolated by neighbouring countries over Doha's alleged support for terrorism and improved relations with Iran, Saudi Arabia's arch regional rival.
Doha denies the allegations.
The event was attended by the 2002 World Cup final referee Pierluigi Collina, now president of the FIFA referees' committee.
He urged the assembled referees to retain their "hunger" to be selected for Russia.
"The months between today and the day when the World Cup in Russia kicks off, this period is everything," he said.
The referees will practice using the Video Assistant Referee (VAR) system during their stay in Doha, said Massimo Busacca, FIFA's head of refereeing, ahead of its expected use in Russia.
Asked how many referees would be selected for the 2018 World Cup, Busacca said FIFA was looking for "quality" not quantity.