Gaza's third international marathon has been cancelled after the ruling Hamas movement refused to allow women to run alongside men, the UN agency for Palestinian refugees said on Tuesday.
UNRWA officials said more than 800 people, nearly half of them women, had signed up to participate in this year's race, which runs the entire length of the coastal territory and was to have taken place on April 10.
"UNRWA regrets to announce that it has had to cancel the third UNRWA marathon which was to be held on 10 April," a statement said.
"This disappointing decision follows discussions with the authorities in Gaza who have insisted that no women should participate."
UNRWA officials say 807 people had entered this year's race - 551 locals and 256 international runners. Of that number, 385 are female - 266 from Gaza and 119 from overseas.
Another 1,600 schoolchildren, girls and boys, were also to have joined the race.
Speaking to AFP, UNRWA spokesman Adnan Abu Hasna said the decision to cancel was taken after the ruling Islamist movement refused to back down over the issue of women and men running together.
"Hamas refused to let women participate in this very important marathon. They told us about this condition several days ago and we went into long negotiations but we failed," he said.
"They pushed us to cancel the marathon and I'm very sorry because it is a very important event for Palestinian refugees."
Two international women runners, including an AFP correspondent, participated in the first Gaza marathon in 2011, alongside hundreds of women and schoolgirls who joined the relay race or walked part of it, with more joining last year.
"Hamas claims that women have never been allowed to run, which is not true, then they decided that only local women could run. Then they decided not to let any women participate," a diplomatic source in Gaza told AFP.
A senior Hamas official confirmed the ban and expressed regret that UNRWA had cancelled the entire event.
"We regret this decision to cancel the marathon but we don't want men and women running together," said Abdessalam Siyyam, cabinet secretary of the Hamas government.
"We did not tell UNRWA to cancel the marathon and we haven't prevented it, but we laid down some conditions: We don't want women and men mixing in the same place," he told AFP, citing Islamic law and traditions.
"We don't want any women running uncovered," he said, indicating the ban was only in place for female runners aged 16 and over.
News that the race had been cancelled over Hamas's ban on men and women running together went down badly with several school children who had worked hard to take part in multiple relay teams.
"This year we have trained and exhausted ourselves for this marathon," said Noora Bulbul, a 13-year-old girl who studies at an UNRWA school.
"Why ban girls from taking part? They know very well that girls swim in the sea alongside boys," she said. "What's the difference?"
Ayman Abdullah, 16, who took part in last year's race, also said he was disappointed that the race had been called off, saying it was "an expression of freedom and which showed that we in Gaza are a civilised people."
This year's race was to have seen 51 Palestinian women running in either the full 42-kilometre (26 mile) marathon, the half marathon or a 10-kilometre (six-mile) dash, while another 215 were registered to join in by walking a two-kilometre or 10-kilometre section of the course.
"UNRWA sincerely regrets the inconvenience this causes those who planned to participate in the marathon," the agency said.