TEHRAN, Iran -- Demonstrators chanted "Down with America" outside the former U.S. Embassy and pelted the British diplomatic compound with eggs and tomatoes Thursday in separate rallies held under tight security but without challenges from opposition groups.
The protests outside the former American Embassy were well-scripted events to mark the anniversary of the 1979 storming of the site -- which began a 444-day hostage crisis and severed Washington's ties with Iran.
Despite the familiar chants against the United States, protesters did not appear to burn U.S. flags in what could be a rare nod of approval to Washington for adding an Iranian militant group to it's terrorist list.
The anti-British demonstration, however, included the Union Jack going up in flames. The protest appeared to be reaction to Iran's announcement that it arrested four suspected members of a Kurdish rebel group with a top official allegedly living in Britain.
Last year, the annual pro-government event outside the brick walls of the former U.S. Embassy brought clashes and chaos to central Tehran after protesters held counter-marches over their claims of massive vote rigging in the presidential election.
But it was among the last major displays of opposition anger on the streets. Embattled authorities began stepping up their crackdowns and threats to quell the most serious domestic unrest since the 1979 Islamic Revolution.
This year, security forces were on high alert for any hint of dissent. Hundreds of anti-riot police joined regular units to fan out across major squares and traffic junctions across Tehran.
The opposition Jaras website posted a statement applauding the "brave" takeover of the U.S. Embassy to protest American support for the pro-Western shah, who had been toppled by the Islamic Revolution months earlier.
Washington cut diplomatic ties after militant students stormed the embassy, holding 52 hostages for 444 days.
But the Jaras statement also warned Iran's leaders to "learn a lesson" from the power of protesters in the Islamic Revolution and "don't go farther down the path of selfishness and despotism."
Outside the former embassy, crowds -- including many school children bused to the event -- chanted anti-American slogans and taunted effigies of Uncle Sam and President Barack Obama.
But protesters did not burn U.S. flags, which has been a feature of rallies to mark the embassy takeover for the past three decades. It was not clear, however, whether this was officially sanctioned restraint.
Iran on Thursday welcomed the U.S. State Department decision to put the Iranian Sunni militant group Jundallah, or Soldiers of God, on the U.S. terrorist list -- which includes Al Qaedaand the Iranian-backed Hezbollah.
Jundallah, which is fighting for Sunni rights in predominantly Shiite Iran, has been blamed for a series of attacks including a mosque bombing in July that killed about 30 people.
Sadegh Zibakalam, a professor of political science at Tehran University, said the absence of burning U.S. flags at the rally could be "a sign of respect" by Iran's leaders.
But President Mahmoud Ahmadinejad on Wednesday did not signal any softening of Iran's position on uranium enrichment -- the central source of tension between Tehran and Washington -- before possibly restarting talks with the United States, Britain and other world powers on the issue.
The rally outside the British Embassy was staged just hours after Iran said it arrested four suspected members of Kurdish rebel group with links to Britain.
State-run Press TV quoted a statement from Iran's Intelligence Ministry saying the arrested men are part of a faction known as the Koumaleh Party. It claimed the men were based in the Kurdish region of northern Iraq and received orders from a Koumaleh commander going by the name Jalil Fattahi. Iran says Fattahi lives in Britain.
The British government dismissed the allegations as "another in a long line of slurs against the United Kingdom from the government of Iran."
The reported arrests follow increased violence in the Kurdish area of western Iran, where various groups have been battling for decades for more autonomy and freedoms. The fight mirrors a wider and bloodier campaign by Kurdish rebels in Turkey since the 1980s.
The claims further strain Iran's tense relations with Britain. Iran has long accused the British of supporting opposition groups, a charge that London denies.
There is a long history of baseless Iranian allegations against the U.K.," a British government statement said.
The Iranian statement did not give details of the slayings allegedly linked to the arrested men.
Last month, gunmen opened fire on a police patrol in Sanandaj, the main city in Iran's Kurdistan province, killing four officers and a bystander.