IRAN announced the arrest of a US-based terror-group leader on Saturday, accusing him of plotting to overthrow the government and planning a string of terrorist attacks.

The Ministry of Intelligence said they had detained Jamshid Sharmadh, the alleged head of the little-known Tondar terrorist group, which seeks regime change in Iran and the restoration of the monarchy.

No details on the nature of the operation or where the arrest was made were disclosed, but the ministry said that it would announce details at a later stage.

Mr Sharmahd is suspected of masterminding the 2008 Shiraz Seyed al-Shohada mosque bombing, which killed 14 people and wounded 215, Iranian officials explained.

Footage on Iranian state TV showed a blindfolded man identifying himself as Mr Sharmahd, who authorities said “directed armed and terrorist acts in Iran from America.”

Two men associated with the group were arrested and executed in 2010 for their role in the mosque attack.

Mr Sharmahd appeared to admit complicity, saying: “They needed explosives and we provided it.”

Tondar is believed to be responsible for the 2010 assassination of Iranian nuclear physicist Masoud Alimohammadi and is accused of planning further terror attacks, including a plot to blow up the Sivand dam in Iran’s southern Fars province.

Iran has urged Washington to extradite individuals associated with Tondar. But the US does not classify it as a terrorist group and allows it to operate freely in the country.

Tondar has a base in Los Angeles from which it runs TV and radio services calling for the overthrow of the Iranian government.

The US “must be responsible for supporting terrorist groups which are inside of this country and carry out and lead terrorist acts against the Iranian people,” Foreign Ministry spokesman  Abbas Mousavi  said.