Iran filed a diplomatic complaint Monday over frustration that members of its men’s national volleyball team were held for up to four hours at O’Hare Airport after flying into Chicago for an international tournament.

Members of the men’s team were held and questioned by U.S. authorities at the airport for up to four hours on Sunday, according to an Iranian news report.

Officials with United States Customs and Border Protection said the matter was professionally handled and only a few members of the team experienced long delays.

”Only four members of the team experienced a wait time of longer than 20 minutes after arriving into Chicago O’Hare International,” a statement CBP emailed to the Chicago Sun-Times Tuesday said.

“The entire Iranian team was processed professionally per CBP policy and admitted into the United States without incident.”

CBP processed 24 members of the Iranian volleyball team that arrived at O’Hare on three separate international flights over a five-hour span from Frankfurt, Vienna and Istanbul, over a nearly five hour span into Chicago, according to the statement.

The Fédération Internationale de Volleyball, which organized the international play being held in northwest suburban Hoffman Estates and an upcoming tournament Wednesday through Sunday at the Credit Union Arena 1 on the campus of the University of Illinois at Chicago, said in an statement emailed to the Sun-Times that while “many of the Iranian delegation were not detained for an unusual period, those that were allegedly detained are understandably upset.”

FIVB officials planned to “discuss the alleged issues with relevant authorities to find ways of preventing this from happening at future FIVB events in the USA.”