Reports in the Iranian media say security forces have arrested the British ambassador to the country as he was trying to foment unrest in the streets of the capital Tehran.

The semi-official Tasnim news agency said late on Saturday that Robert Macaire had been briefly detained during a protest in front of the Amir Kabir University in downtown Tehran where he was organizing and provoking people angry at the government�s way of handling the aftermaths of a plane crash earlier this week.

The ambassador was released several hours later but it is believed that he will be summoned (by Foreign Ministry) tomorrow and the case will be pursued, said the report.

Britain�s Foreign Secretary Dominic Raab issued a statement condemning the detention of Macaire, saying it had been carried out without grounds or explanation.

However, Tasnim cited informed sources as saying that Macaire had been holding secret meetings inside a shop opposite the main gate of the Amir Kabir University to monitor the developments that led to the protest on Saturday.

Police in Tehran was forced to use tear gas to disperse some of the protesters gathering in front of the university hours after Iranian armed forces headquarters issued a statement clarifying circumstances surrounding the crash of a Ukraine International Airlines plane on January 8 which killed 176 people on board.

The statement said the Boeing 737-800, on its way to Kiev and ultimately bound for Canada�s Toronto, had been shot down accidentally hours after Iran fired missiles at two American military bases in neighboring Iraq.

Some of students holding vigils for the victims of the crash in Tehran on Saturday said they were not happy with the way the armed forces had clarified the issue, saying it added to the bitterness of the tragic incident.