Several people have been taken hostage in Paris by an armed man.
Videos and images from the scene posted on social media show police officers outside a building in central Paris's Petites Ecuries street.
The man also claims to have an accomplice outside the building.
France has been on high alert after a series of jihadist attacks in the past three years, most recently a Saturday night knife attack by a man in Paris last month in which one person was killed.
Police said the incident was not believed to be terror-related. The hostages were held in a ground-floor office in a crowded neighbourhood.
Iran's semi-official ISNA news agency reported that a spokesman for Iran's Foreign Ministry, Bahram Ghasemi, said the Iranian Embassy in Paris stood ready to help "considering the importance of people's lives and human aspects of the issue".
Officials at police headquarters would not immediately confirm whether the person holding the hostages was armed or describe the nature of his demands. Police swept vehicles in the area with a device but found nothing, he said. The attacker, who appeared to be brandishing a fake weapon, had doused his remaining two hostages in petrol, the source said.