TEHRAN, Iran (AP) - Opposition protesters returned to the streets of Tehran Wednesday for the first time in nearly two months, clashing with security forces just blocks from a government rally to mark the 30th anniversary of the U.S. Embassy takeover.
The scenes of defiant chants, tear gas and baton-wielding police recalled the unrest that followed the disputed presidential elections in June. But the latest marches drew far fewer demonstrators and suggested the relentless pressure by authorities could be taking a toll on the opposition.
It also displayed the pinpoint counter strategy of opposition groups: staging rival marches during key state-backed events to gain maximum exposure as they try to reassert their voice.
The contrasts were vivid on a day of major symbolic importance to the Iran's leadership.
People chanted "Death to America" and walked over U.S. flags outside Washington's former embassy. Meanwhile, hundreds of opposition marchers in nearby Haft-e-Tir Square denounced President Mahmoud Ahmadinejad with cries of "Death to the Dictator" and trampled a poster of Supreme Leader Ayatollah Ali Khamenei, witnesses said.
Marchers also called on President Barack Obama to pick a side, as his administration pursues talks with the government.
"Obama, Obama, you are either with them or with us," they chanted in Farsi in an amateur video clip widely circulated on the Internet.
In Washington, the White House called for an end to the violence against anti-government protesters. White House press secretary Robert Gibbs said Obama administration leaders are following reports of the unrest and "hope greatly that violence will not spread."
Several thousand protesters joined the marches — crowds far smaller than the height of the outrage after claims that Ahmadinejad stole the election by fraud.
But authorities were ready with the same sweeping measures: dispatching paramilitary units to key locations and disrupting mobile phones, text messaging and Internet access to frustrate protest organizers.
The main marches were quickly dispersed by security forces — including paramilitary forces and militiamen linked to the powerful Revolutionary Guard — who used clubs and tear gas, said witnesses, who spoke on condition of anonymity because of fear of reprisals from authorities.
Pro-reform Web sites said police fired into the air to try to clear the square — about half a mile from the former U.S. Embassy. The report could not immediately be independently verified.
Groups of protesters were chased within a few blocks of the former U.S. Embassy as security forces fanned out through Tehran's center.
Some demonstrators were injured and arrested, witnesses said, but a clear number could be independently obtained. There were no reports of serious injuries.
In many ways, it was a replay of the last time opposition groups took to the streets in mid-September to coincide a state-sponsored day to denounce Israel. But those marches brought tens of thousands of protesters and a more militant response — with protesters throwing stones and setting fires ablaze.
The smaller turnout raised questions about the long-term stamina of the opposition after facing months of arrests and crackdowns from authorities.
"I don't think the opposition is as able to get as many people in the streets as they were after the election," said Alireza Nader, an Iran affairs analyst for RAND Corp. in Washington. "But today's events show there is still opposition that is willing to come out."
The opposition movement has also evolved since the election fallout touched off Iran's worst internal unrest since the 1979 Islamic Revolution.
Protests still wear the green colors that symbolized the campaign of Mir Hossein Mousavi, who claims Ahmadinejad stole the election from him through rigged ballots.
But its now expanded into a catchall movement for complaints that include the unlimited powers of the ruling clerics, Iran's sinking economy and its international isolation. Its wider reach has managed to draw in other political leaders and clerics who have challenged Ahmadinejad and his allies at a sensitive time, including Iran's talks with the West over its nuclear program.
"I think the long-term crisis for the government isn't over," said Nader. "There is still a strong sense that the Ahmadinejad government is not legitimate. The sentiment is strong among the people, in some of the ruling elite and the clerics."
A pro-reform Web site, meanwhile, said militiamen on motorcycles prevented Mousavi from leaving his office to attend the marches.
Another leading opposition figure, Mahdi Karroubi, fell to the ground after being overcome by tear gas, according to a posting by his son Hossein on Karroubi's Web site. Karroubi did not need medical attention, his son said.
The full scope of Wednesday's protests was difficult to determine. Some opposition groups also reported demonstrations in other cities such as Shiraz and Isfahan.
Media restrictions now limit journalists to covering