Officially, the angry street demonstration marked the 25th anniversary of the student takeover of the former U.S. Embassy, when 52 Americans were held hostage for 444 days. Unlike past commemorations, this one focused just as much on the future - and the potential for another showdown with the United States during Bush's second term.

Bush - not Jimmy Carter, who was president during the 1979-81 hostage drama - was the centerpiece of the protest. Three massive photographs of the president were part of the backdrop for a series of speakers who blasted current U.S. policies. The subtext throughout the noisy morning protest, held in front of the former American compound that is now a Revolutionary Guards training center, was the escalating dispute between Washington and Tehran over Iran's nuclear energy program.

''Nuclear technology is our right and we are not going to surrender our rights to the United States or Europe,'' vowed one of several such banners waved by teen-age schoolgirls packed into the crowd of thousands. The two-hour rally ended with a statement, read to roaring chants of ''Allahu Akbar'' (''God is great''), that Iran would never give up its right to nuclear technology.

Bush's invasions to topple governments in Iraq and Afghanistan, which both share long strategic borders with Iran, have led many Iranians to suspect the president is eyeing some form of confrontation with them.

''If America is going to attack us, it's important to protect ourselves,'' said Shiva Mosapour, a 16-year-old high school student.

Mosapour's assumption about Bush's intentions during his second term echoed many in a new young generation that doesn't remember the monarchy - or the seizure of the U.S. Embassy.

For her, the demonstration was appropriate because it fell on the U.S. Election Day 25 years later.

Older Iranians at the demonstration were equally critical. ''Bush will bring America bad luck,'' said Fatima Hoshmahd, a 70-year-old housewife who lost a son during the Iran-Iraq war of the 1980s. ''Why did people vote for Bush when he brought such bloodshed to this region?''