Iran's Revolutionary Guards, who helped to quell protests after last June's election, warned the opposition Monday not to use anti-US rallies this week to stage new demonstrations. Moderate opposition leader Mirhossein Mousavi appeared to urge his supporters Saturday to take to the streets on Nov. 4, the 30th anniversary of the US embassy takeover in Tehran. The authorities, seeking to avoid any repeat of the huge demonstrations that erupted after the disputed election won by President Mahmoud Ahmadinejad, say security forces will confront any illegal gatherings. The Guards called on the Iranian people to “exercise vigilance in regard to the likelihood of mischief and plots by the enemy's agents and some unaware and misguided people on Nov. 4”, the official IRNA news agency reported. “The Iranian nation will not allow any group to impose itself and use diversionary and false slogans on Wednesday,” it quoted a Guards statement as saying. Anti-Western rallies usually take place outside the old US embassy – now called the “den of espionage” in Iran – to mark the day in 1979 when radical students scaled its walls and took 52 Americans hostage.