Iranian police briefly detained two European diplomats at a mixed-gender party, which are illegal under Iranian law, the semi-official Tasnim news agency said on Saturday.
A British and a Dutch diplomat were released in the early hours of Friday morning after being identified as foreign government workers.
The report said the party in the capital, Tehran, was attended by several men and women, but did not elaborate or specify if alcohol was present.
Authorities in Iran regularly carry out raids on private parties in attempt to clampdown "corrupting influences" in the Islamic Republic.
In August, they arrested dozens of "half-naked" youths during a party in Isfahan, where
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Alcohol and holding mixed gatherings of men and women who are not related are banned under the country's strict moral laws, which were introduced after the 1979 revolution.
Crimes involving drug abuse, adultery and "spreading corruption" can land the accused with a death penalty in Iran. Lesser offences often result in fines, jail terms or lashes.
Last week, thirty people were arrested in Iran for wearing "inappropriate" clothes while taking part in a yoga session.
Local justice department official Massoud Soleimani said participants of the class were dressed in "inappropriate outfits", and had "behaved inappropriately" by taking part in the mixed class.
This article has been adapted from its original source.
