Two young men have been arrested after they threw stones and incendiary devices at the Iranian embassy in Bern on Wednesday.
The building was not damaged in the attack, but some damage was done to cars parked nearby.
The two unidentified men were detained by the police and by embassy guards.
The reason for their action is not yet known, and an investigation has been opened, the police said.
Earlier in the day the Swiss foreign ministry had added its voice to worldwide condemnation of Tuesday’s attack on the British embassy in Tehran. Violent demonstrators were demanding its closure after Britain imposed further sanctions against Iran to persuade the country to abandon its nuclear programme.
Switzerland called on those responsible to be put on trial, and demanded that the security of diplomats should be guaranteed.
However, the Swiss embassy in Tehran remains open.