Tikrit, Iraq (CNN)ISIS is gone, but the fear remains. As Iraqi forces, aided by Shiite militiamen, took control Wednesday of the northern city of Tikrit, they found vehicles laden with explosives and buildings that might be booby-trapped. CNN senior international correspondent Arwa Damon, who was in Tikrit on Tuesday, saw a large mechanical digger packed with explosives that Iraqi forces had to disarm. The troops, she said, were cautious when they entered buildings in case they were wired to explode. Plumes of smoke rose from burning buildings in the background. Near former Iraqi dictator Saddam Hussein's presidential palaces compound -- Tikrit is Hussein's birthplace -- the CNN team also saw a destroyed truck with a large machine gun mounted on the back. Iraqi forces said they had fired an RPG at the truck, killing three ISIS fighters. ISIS was ejected from the palaces compound in fierce fighting, they said, adding that there may still be booby traps. Federal police said they dismantled hundreds of IEDs (improvised explosive devices) Wednesday. CNN heard at least 16 explosions, some very loud, which police said were controlled. The potential booby traps were political as well as physical. Officials are concerned about the behavior of the conquerors, particularly the Iranian-backed Shiite militiamen who helped Iraqi troops. Officials fear the militiamen might take "scorched earth" reprisals for the reported massacre of Shiite air force cadets by ISIS fighters in Tikrit last year. Much of the population of Tikrit is, like ISIS, Sunni Muslim. And officials fear that reprisals by Shiite militias against the Sunni population could stoke local anger, jeopardizing the government's ability to hold onto Tikrit and pull the country together. Sectarian resentment helped fuel the rise of ISIS in the first place. 'Where are our sons?' demand families of soldiers captured by ISIS . Still, the liberation of Tikrit from the terrorist group, which is also known as ISIL and calls itself the Islamic State, represented a significant victory for the Iraqi government, which had tried -- and failed -- to retake the city many times before. Iraqi  Prime Minister Haider al-Abadi arrived Wednesday to claim the victory, which took place a year after the city was first attacked by ISIS. Al-Abadi, who is also Iraq's top military commander, had announced the previous evening on Iraqiya TV that the city was under the control of Iraqi forces. Iraqi forces continued to clean out pockets of resistance Wednesday, said Interior Minister Mohammed al-Ghabban, who was also in the city. But he said the Iraqi government would be in full control shortly. "The enemy has been defeated, and it has lost all its capabilities," al-Ghabban said. "In the coming hours, the battle will end." Iraqi security said that the few ISIS militants left in the city are hiding inside houses hoping to escape in the dark. ISIS' nine-month dominion over Tikrit was marked by brutality. In addition to the reported massacre of the 1,500-plus air force cadets at Camp Speicher in June, ISIS is believed to have buried victims in mass graves and to have destroyed an Assyrian church that had graced Tikrit since the eighth century. The push into Tikrit came days after U.S.-led airstrikes targeted ISIS bases around the city. Al-Abadi said those tactics would now be replicated in other areas. Brett McGurk, the U.S. deputy special presidential envoy to the Global Coalition to Counter ISIL, tweeted that the coalition's airstrikes had destroyed numerous ISIS shelters. "We will continue to support courageous Iraqi forces operating under Iraqi command as they work to reclaim their territory from #ISIL," McGurk tweeted. The key to victory in Tikrit this time, the Prime Minister said, was surprise. But help from the coalition of Shiite militiamen and volunteers also played a part. The militia members, estimated to number around 20,000, are backed by Iran. The offensive marked the first open participation of Iranian advisers on the front lines in Iraq. The victory in Tikrit sets the stage for Iraqi forces to take back an even bigger prize -- Mosul, Iraq's second-largest city. A U.S. official said in February that up to 25,000 Iraqi troops plan to return to Mosul in April or May in an effort to retake the city. Don Melvin wrote this report in London. Arwa Damon and Hamdi Alkhshali reported from Tikrit and Jomana Karadsheh from Baghdad.
Tikrit is under the control of Iraqi forces, Iraqi Prime Minister says .
ISIS departs, leaving city strewn with booby traps, explosive-filled vehicles .
Officials hope to avoid Shia reprisals for ISIS slaughter of air force recruits .