After training for months for the Tehran marathon, a group of female runners were told – just weeks before the big day – they were not allowed to take part, and so staged their own race instead.

Around 160 women has registered to take part in the TehRUN, a 42km race around the Iranian capital.

After being denied entry to the race at short notice by the organisers, the group risked being arrested by Iranian authorities by taking part in a secret 32km run outdoors, through the city's Beheshte Madaran park.

Men and women are not permitted to participate in sports events together in Iran.

Initially, the runners believed they would be allowed to take part in the full marathon, under the condition they wore a headscarf to cover their hair, long-sleeved shirts that reached down to their hips and avoided wearing shorts.

On the day of the race, however, the women were told they could only participate in a separate 10km run, not the half marathon or full marathon. Women who wanted to run the full distance would have to use an indoor track inside a stadium.

Manal Adel Rostom, a professional runner from Egypt, told the Independent she was glad women "spoke up" and organised their own race.

Tehran marathon
Foreigners and locals watch the first international Tehran marathon in the Iranian capitalAtta Kenare/AFP/Getty Images

"I just feel that when women speak up for themselves that's when real change comes around. As a Middle Eastern woman to see women being empowered in this way and see women run in the streets for the first time means a lot to me, of course," she said.

The race was organised by Dutchman Sebastiaan Straten, who told CNN months of preparation had been undermined by Iran's "challenging political climate".

American citizens who had signed up for the run – the first international marathon in Iranian history – reportedly also struggled to obtain visas to enter the country.

"I sincerely regret the promises I had made to female runners that they would be able to run, and (to) the US and UK runners who were very motivated that that were not able to secure their visas."