Iranian police will confront any "illegal" gatherings on Nov. 4, when the Islamic Republic marks the 30th anniversary of the seizure of the U.S. embassy in Tehran, a semi-official news agency reported on Sunday.
Mehr News Agency reported the warning by deputy police chief Ahmadreza Radan a day after opposition leader Mirhossein Mousavi appeared to urge supporters to take part in rallies on that day.
In a statement posted on his www.kaleme.com Web site, Mousavi said he would press ahead with his efforts for political change in Iran following a disputed June presidential election, which he says was rigged in favor of incumbent Mahmoud Ahmadinejad.
Opposition supporters clashed with police and government backers on Sept. 18, at the annual demonstrations in support of the Palestinians.
"The duty of the police is to protect public order, and based on the law we are obliged to prevent any move disturbing the public order," Radan said.
An Iranian MP, Hasan Malek-Mohammadi, also issued a stern warning to the opposition, IRNA news agency reported.
"Those individuals and groups that act against the revolution's pillars and the views (of Supreme Leader Ayatollah Ali Khamenei), will be considered as Mohareb (fighting against God) and corrupt on earth," said Malek-Mohammadi, referring to a crime which could be punishable by death in Iran.
"On this day, political groups ... should act in line with the country's national interest," he said.
Anti-Western rallies usually take place outside the old U.S. embassy to mark the day in 1979 when radical students scaled its walls and took 52 Americans hostage, holding them for 444 days. Washington cut diplomatic ties with Tehran in 1980.
Some reformist Web sites have called on people to gather outside the Russian embassy instead, in an apparent protest at Moscow's swift recognition of Ahmadinejad's election victory.
Iranian security officials have ordered the opposition not to hold demonstrations on that day.
Apart from sporadic incidents, the streets of Tehran have returned to normal since June's disputed election, which sparked Iran's worst street unrest since the Islamic revolution three decades ago.
The elite Revolutionary Guards and an allied Islamic militia quelled the huge opposition protests that erupted in the days after the vote and thousands of people were arrested.
Most of the detainees have since been released, but more than 100 senior reformers, activists, journalists and others have been put on trial, accused of fomenting street unrest. The opposition has denounced the court sessions as "show trials."
The authorities have portrayed the demonstrations as a foreign-backed bid to undermine the Islamic state and reject charges of vote rigging.
The opposition says more than 70 people were killed in the post-election violence. Officials say the death toll was half that and members of the security forces were among the victims.
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