Security forces detained and later released a British and Dutch diplomat at a mixed-gender party in the Iranian capital city, Tehran.

According to Islamic Republic laws, men and women who are not relatives cannot mix in a party. In large non-family parties or receptions men and women have to be in separate rooms or areas.

The Islamic Revolution Guards Corps (IRGC)-run Tasnim news agency reported, "The two were arrested on Friday, but released early Saturday morning after security forces discovered their identity in custody."

The party was held in one of the posh areas of the city, Velenjak, Tasnim says without further elaboration.

The Islamic Republic judicial department has not yet reacted to the news, and the identity of the two diplomats has not been revealed.

Arresting foreign diplomats in Iran is not unprecedented.

The Japanese Embassy in Tehran said on Sunday, August 21, 2016, that Ambassador Hiroyasu Kobayashi was briefly detained and questioned in a raid on a similar party by security forces, and that a protest had been lodged with the Iranian Foreign Ministry.

The incident happened when Kobayashi and his wife attended a dinner hosted by a local acquaintance. In total dozens of people, including other foreign diplomats, attended the event at which alcohol was served.

Alcohol consumption is also banned by Muslims in the clergy-dominated Iran, although drinking alcohol is widespread.

Midway through the dinner, security authorities stormed the party and prevented the hosts and their guests from leaving the venue as well as using their cell phones.

At that time, Kobayashi was not carrying a photo identification card known as a "diplomatic card" issued by the Iranian Foreign Ministry. He instead showed off his business card, which was ignored, and was questioned.