New details added (the first version was posted at 17:08)
Clashes began between demonstrators and police in the Iranian capital and several cities of the country, the official website of opposition Kaleme.com reported.
According to information, clashes between police and protesters occur in Tehran, also in the Esfahan city, police has arrested dozens of demonstrators.
The number of demonstrators, especially in the capital, increases.
The Iranian police used tear gas to disperse the participants of rallies ongoing in Tehran on Monday, the Iranian opposition's official website Kaleme.com reported.
Iran's National Security Forces used tear gas against protesters gathered in the squares Azadi and Ingilab in Tehran.
The Iranian site RaheSabz.net reported that police fired at demonstrators in the "Azerbaijan" avenue and one person got injured.
Kaleme.com reported that more than thousands demonstrators went on the streets in the cities of Shiraz and Isfahan. The police tried to disperse the protesters.
Rallies have already spread to cities Kirmanshah, Reshd and Khomeneisheher. Access to mobile communications has been closed in many Iranian cities, particularly in Tehran.
Ex-Iranian President Mohammad Khatami, as well as former Interior Minister Abdullah Nuri, has been put under house arrest
A protest action has started on the squares of Azadi and Engelab in Tehran, Kaleme.com reported earlier.
On Monday Iranian police also surrounded the opposition leader Mir Hossein Mousavi's house and blocked all phone lines to prevent him from participating in a rally in support of the Egyptian protesters, Kaleme.com opposition website reported.
According to the website, four representatives of law enforcement agencies in civil barred Mousavi's wife Zahra Rahnavard's way when she intended to leave the house.
Last week, one of the opposition leaders Mehdi Karroubi was put under house arrest.
According to his son, who tried to visit his father and was stopped by police outside Karroubi's house, he was told that all family members and friends, except spouse are not permitted to visit Karroubi. The ban will be valid until Feb.14.
According to the website, presumably Karroubi was arrested due to the fact that he and Mir Hossein Moussavi on Monday sent a letter to the Interior Ministry with a request to give them and their supporters a permission to hold a rally in support of the peoples of Egypt and Tunisia on the Imam Hussein and Liberty squares on Feb. 14. It was planned that the rally will be held at 15:00 local time on Monday.