Iran's semi-official Tasnim news agency is reporting that police in the capital, Tehran, briefly detained two European diplomats at a mixed-gender party, which are illegal under Iranian law.

Saturday's report said a British and a Dutch diplomat were released after being identified as foreign government workers in the early hours of Friday morning.

The report said the party was attended by several men and women, but did not elaborate or specify if alcohol was present.

In Iran, it is illegal to drink alcohol or hold mixed parties of Muslim men and women who are not related. Both activities are permitted for the country's small Christian minority.