UPDATE 8 August: All of the detained Tehran "water fighters" --- the number is estimated to be 10 --- have been released on bail after they were charged with "anti-regime propaganda".
UPDATE 2100 GMT: Mardomak reports that 30 people have been arrested in Bandar Abbas in southern Iran over a "water pistol fight".
UPDATE 1600 GMT: TehranLive have now withdrawn the photographs which we have used in this entry. Because this may have been done to protect the identity of the adults in the water fight, we are also withdrawing the pictures of those who could be detained.
UPDATE 0650 GMT: Thirty youths playing water games in a park in Kermanshah have been arrested by morality police forces "for guidance"
Forget all the political conflict inside Iran, the hot story for the international media this week has been how the hot Tehran weather --- and a water fight in a park --- led to the arrests of young men and women.
An event, planned and organized on Facebook, brought about 800 people to the Garden of Water and Fire, armed water guns, to splash water on each other.
All good fun, right? Well, not for conservative websites who seized on photos of the gathering to accuse the water-fighters of immorality and corruption. Bultan News said the Facebook-organised fun was part of "the soft war with its cyber-dimension and the influence of social networks --- we have to stop this influence as soon as possible, without any delay".
Last Sunday, Tehran Police Chief Hossein Sajedinia, said a group of young Tehran residents had been arrested and warned that the police would act against others who disrupted "public order and security".
And the politics of the event? Well, it did not come from the participants --- one of whom wrote, "All we want is a bit of joy" --- but from the newspapers reporting on it. The hard-line Raja News accused Tehran Mayor Mohammad Baqer Qalibaf and his advisors of responsibility. Hamshahri, owned by the city of Tehran, said Raja News was lying.
In any case, justice had to be served. Not only was the head of the Religous Police brought on television to explain the seriousness of the crimes --- some of those arrested gave their "confessions".
So is that the end of this party? Maybe not --- the Facebook page for the Water Fight has a photo with the date "2 September".