2009, The Washington Post TEHRAN -- Street battles between Iranian security forces and anti-government demonstrators erupted Wednesday after opposition supporters tried to disturb state-sanctioned rallies marking the 30th anniversary of the takeover of the U.S. Embassy, witnesses and state media reported. Security forces posted on nearly every street corner in the city center heavily outnumbered protesters and broke up crowds using batons, tear gas and warning shots, state media reported. Foreign media representatives were allowed to cover only the government-sanctioned rally, in front of the building that formerly housed the U.S. Embassy in Tehran. In Washington, President Obama called on the Iranian government to decide whether it wants to focus on the past or the future. 'Iran must choose,' he said in a statement marking the 30th anniversary of what he described as the unjust hostage-taking. Clashes were reported in several places in the city center and in Shiraz, a city 420 miles south of the capital. Most demonstrators were unable to convene for long periods, as motorcycle units of the Revolutionary Guard Corps arrived to disperse them. Motorcycles belonging to a military organization also prevented Mir Hossein Mousavi, the main opposition leader, from leaving his office, a Web site affiliated with Mousavi reported. The motorcycle squad was posted outside Mousavi's office at the Academy of Arts and was not allowing him to leave the premises, the Kaleme.org Web site said. Another team was stationed at Mousavi's house. 'He was under de facto house arrest today from the early morning,' the Web site Rahesabz.net reported. The anti-government protests, which have been planned for weeks via the Internet, graffiti messages and illegal leaflets, were smaller than similar demonstrations staged in September. Analysts said they nevertheless showed the persistence of anti-government groups in challenging Iran's political leaders after President Mahmoud Ahmadinejad's disputed June 12 election victory. A bodyguard for 72-year-old opposition leader Mehdi Karroubiwas hit by a tear gas canister as Karroubi tried to participate in an anti-government gathering on the central Haft-e Tir Square. Karroubi was warned by authorities that there would be an assassination attempt against him, his son Taqi Karroubi told Ayandehnews.ir, a Web site often critical of the government. Iranian authorities had warned protesters against attempts to disrupt or overshadow the annual gathering outside the former U.S. Embassy, which was stormed by militants in 1979 nine months after the Islamic revolution. A total of 52 Americans were held hostage for 444 days. Media restrictions now limit journalists to covering state media and government-approved events, such as the rally outside the former embassy. Mobile phones and Internet access were blocked Wednesday, in a repeat of tactics used by authorities after the election. Thousands convened at the state-sanctioned rally, holding up signs saying, 'Death to America,' an official slogan in Iran since the hostage crisis. Young men in military fatigues burned a homemade American flag and danced around the flames, punching their fists in the air. 'The Americans say they are worried about religious democracy in Iran,' said Gholam Ali Haddad Adel, a former head of parliament, referring to a recent report denouncing Iran for mistreating minorities. 'But they get upset when Islamic parties win free elections.' 'No compromise, no surrender: Battle with America!' one speaker shouted, as the crowd repeated his words. Addressing the leaders of the anti-government movement, Haddad Adel accused them of betraying their country. 'What will they answer to the families of the martyrs? To the pure children of the revolution? What will they answer to our supreme leader?' he asked, accusing protesters of doing the bidding of the United States. 'They will have to answer to the nation.' 'Thirty years ago today, the American Embassy in Tehran was seized,' Obama said in his statement on Iran. 'The 444 days that began on November 4, 1979, deeply affected the lives of courageous Americans who were unjustly held hostage.' He said the embassy takeover 'helped set the United States and Iran on a path of sustained suspicion, mistrust and confrontation,' adding, 'I have made it clear that the United States of America wants to move beyond this past, and seeks a relationship with the Islamic Republic of Iran based upon mutual interests and mutual respect.' Staff writer William Branigin in Washington contributed to this report. 