LONDON, U.K. — On the eve of the 30th anniversary of the takeover of the U.S. Embassy in Tehran, jumpy Iranian authorities declared they had broken up two new plots aimed at destabilizing the Islamic Republic.

Five “terrorists” were detained as part of a plot to assassinate a prominent Iranian political figure, the news agency ISNA reported quoting Intelligence Ministry sources, who blamed the CIA. The high-profile regime official was targeted twice, according to the report — once in August during the parliament’s swearing-in ceremony and again in the past week — in a move intended to “create conflicts among different political factions.”

The second alleged plot was foiled when security forces arrested three people linked to a royalist group. They were planning on setting off bombs targeting the U.S., British and Russian embassies, under cover of tomorrow’s regime-organized protest, “to foster insecurity and terror,” according to the conservative Javan online news agency.

The Iranian government is nervous about the continuing post-election unrest that started after the disputed June 12 presidential elections and is now rumbling into a fifth month. And maybe it has reason to worry, as a prominent exile has called for the restoration of the monarchy and one source reports that exiles have been smuggling arms into Iran from Turkey.

Last month, Iran experienced its largest single military loss of life since the conclusion in 1989 of the eight-year Iran-Iraq war when an explosion in Iran’s restive Balochestan province killed more than 30 members of the Revolutionary Guard, including several top officials. The Iranian government blamed the Baloch separatist group Jundollah and alleged that it receives U.S. support.

Thousands of people have been arrested in the past months of unrest and five men condemned to death in a series of mass televised trials condemned as show trials by the opposition. Royalist groups have been particularly targeted, with four of the men condemned to death for purportedly belonging to a royalist group called the Iran Monarchy Committee that advocates restoring the Pahlavi dynasty overthrown by the 1979 Islamic Revolution.

The arrests, imprisonments, death sentences and reports of widespread torture and rape have cowed a usually argumentative society. One Iranian university professor contacted in Tehran refused to comment, explaining that “I have been banned from speaking to foreign media.”

Royalist groups may be increasing their mobilization in response to a call by Reza Pahlavi, the son of the deposed Shah, to “come together inside and outside Iran in support of the higher ideals of secular democracy, majority rule and respect for human rights.”

An Iranian speaking to GlobalPost in Ankara told how a royalist exile had described stockpiling light automatic arms in Turkey’s capital city. The weapons were recently funnelled into Iran through the Kurdish and Azeri smuggling networks, he said. The individual believed the weapons were sent in to take advantage of the ongoing political turmoil in Iran and to compound domestic unrest.

“He told me their house was packed with weapons up until a few days ago when they smuggled it into Iran,” said the individual, who refused to disclose the royalists' names for fear they would be targeted by Iranian agents in Turkey.

The government is clearly worried about the threat of arms being smuggled into Iran. An Iranian govenrment spokesman announced last month that large quantities of weapons have been smuggled into the country since the June presidential elections.

Networks have sprung up away from the cities where the government’s authority is weakest and in neighboring countries such as Armenia and northern Iraq to shelter political opponents of the regime on the run, according to several individuals in those remote areas.

“Life actually does go on as normal but every now and again there is a crisis,” said one 30-year-old woman who asked that her name be withheld. “The opposition uses any occasion to get onto the streets.”

Wednesday's anniversary of the seizure of the U.S. Embassy in 1979 by radical student followers of Ayatollah Ruhollah Khomeini, the founder of the Islamic Republic, is one such date. The government dubbed it Student Day in the 1980s, closing all schools and universities on the day to encourage pupils to shout anti-Western slogans before the abandoned building of the U.S. Embassy in central Tehran.

The opposition movement, spearheaded by presidential candidates Mohsen Karroubi and Mirhossein Mousavi, has fought back against a violently enforced ban on its supporters’ public demonstrations by infiltrating regime-led demonstrations and shouting slogans against the government of Iranian President Mahmoud Ahmadinejad.

“I’m a bit nervous about tomorrow to be honest,” said Potkin Azarmehr, a London-based blogger and human rights activist who has organized some protests. “Many people will be at work and won’t be able to take time off. If large numbers can’t turn up, it will be very demoralizing.”

Opposition activists are discussing the possibility that the Iranian government has temporarily unblocked filtered internet sites such as Facebook and YouTube in order that it can trace users uploading films of protests shot on their mobile phones and arrest them.

Mohsen Sazegara, a former revolutionary who founded the Revolutionary Guard and is currently an exile in Washington, D.C., has issued a video instructing demonstrators to form heavy traffic jams in front of military bases, link up in human chains and not accept dispersal by pro-regime forces.

“It’s going to be a crazy day tomorrow,” said the 30-year-old woman who didn't want to give her name. “I’ve been trying to get a holiday from the office (to join in the protests) but my request was rejected.”