Volleyball's world governing body said "misunderstandings" in Iran were to blame for female spectators being denied entry to a Beach Volleyball World Tour event.
Allowing women to attend the five-day competition at Kish Island had been a condition of world body FIVB for the Iranian volleyball federation to host the men's event.
Female fans are traditionally barred from attending male-only sports matches in Iran.
FIVB spokesman Richard Baker told The Associated Press "there were some misunderstandings with regard to security" during play on Tuesday.
He said women could then watch games from a cafe overlooking the main court.
"There have been misunderstandings throughout the day, and we have had to seek clarification," Baker said, adding the Iranian federation "has the best intentions but there are cultural issues."
Minky Worden, director of global initiatives for Human Rights Watch, said the decision by Iranian authorities was "far more serious than a 'slight misunderstanding."'
"Brave Iranian women who took the FIVB at its word were turned away at the turnstiles this week," Worden said. "That is a black eye for the sport of volleyball, and a setback for women's rights in Iran.
"This sorry episode highlights the shortcomings of the FIVB's strategy with the Iranian government, and contradicts their claims that all Iranian fans are welcome."
HRW said the 2012 ban on women attending men's volleyball matches emerged after the Iranian Ministry of Sports and Youth Affairs extended the 1979 ban on women attending games in soccer stadiums.
The ban came to worldwide attention in 2014 over the detention of an Iranian-British woman, Ghoncheh Ghavami, who tried to attend a men's volleyball match between Iran and Italy.
Ghavami was detained for several hours and then released but was arrested again a few days later and eventually sentenced to a year in prison for "propagating against the ruling system." She was freed on bail pending an appeal.
