LONDON — The diplomatic standoff between Qatar and its Arab neighbors spilled into the sports world once again Thursday as a Qatari vice president of Asia’s soccer confederation was barred from traveling to the United Arab Emirates ahead of the region’s top tournament.

Saoud al-Mohannadi, vice president of the Asian Football Confederation, was denied permission to travel from Oman to the U.A.E. after airport officials said he wouldn’t be let into the country. The U.A.E., with Saudi Arabia and a handful of other Mideast countries, broke diplomatic relations and severed all ties with Qatar in 2017.

Mohannadi is the chairman of the A.F.C.’s competitions committee, a group with overall responsibility for the Asian Cup. Prohibiting him from traveling to the U.A.E. is the first sign that long-simmering political tensions in the Gulf are likely to have ramifications for continent’s biggest tournament.

Mohannadi immediately wrote a letter of complaint to Sheikh Salman bin Ibrahim al-Khalifa, the Bahraini royal who is the A.F.C.’s current president. The organization said in a statement that it was aware of reports that Mohannadi was being denied the right to travel and that it would investigate. The A.F.C. said it had been “assured of visas and entry permits” for tournament organizing committee members and executives.