Tahrir Square occupied as anger grows over Mubarak verdict Marco Longari / AFP - Getty Images An Egyptian protester wearing a wristband in the colours of his national flag shouts slogans in Cairo's landmark Tahrir Square on Sunday. By Charlene Gubash, NBC News, and Alastair Jamieson, msnbc.com Updated 07:11 a.m. ET: CAIRO -- Hundreds of Egyptians occupied Cairo's central Tahrir Square on Sunday, enraged that a court had spared deposed leader Hosni Mubarak his life over the killing of protesters in the uprising that ended his three-decade rule. They saw the sentence and the acquittal of senior police officers on Saturday as proof that the old regime still wields influence and feared Mubarak could now be acquitted on appeal. Mubarak was handed a life prison sentence. At nightfall on Saturday, up to 10,000 people gathered to vent anger over acquittals on corruption charges even though longtime U.S. ally Mubarak was sentenced to life in prison for failing to stop the killing of 900 protesters in January 2011. By early Sunday morning, a few hundred were still gathered in Tahrir Square, where many said they would stay until those killed in the uprising were avenged. NBC's Charlene Gubash reported that the atmosphere in Tahrir Square was "more like an open air party than a demonstration, with people setting off fluorescent fireworks...clapping, singing and chanting spontaneously." Former progressive candidates who made failed bids for the presidency came to encourage the crowd to unite against loyalists to the old regime and the results of the election. One former candidate, activist Khalid Ali, rallied the masses to build a build a national coalition to save the revolution. The long-awaited Mubarak verdict deepened fear among many pro-democracy campaigners that recent developments are reversing Egypt's emergence from decades of autocratic rule. "This was not a fair verdict and there is mass rejection of the judge's ruling," said one protester, Amr Magdy. Tahrir will fill up again with protesters. In Egypt the only way you can get any justice is by protesting because all the institutions are still controlled by Mubarak figures. Many of the young liberal and left-wing revolutionaries who began the uprising were dismayed when their own candidates lost the first round of the presidential election last month. A run-off on June 16 and 17 will pit Mubarak's last prime minister Ahmed Shafiq, who holds Mubarak as a role model, against the candidate of the socially conservative Muslim Brotherhood, Mohamed Mursi. Dozens of young men ransacked Shafiq's campaign office in Fayoum south of Cairo overnight, the second such attack in recent days, state news website al-Ahram reported. A Shafiq campaigner in Cairo said he was not aware of the attack. Footage posted on Al-Ahram's website showed youths destroying and burning Shafiq's pictures and banners and others chanting: "Fayoum says Ahmed Shafiq is feloul," an Arabic word used to refer to remnants of the Mubarak era. The Muslim Brotherhood party called on their huge membership to come into the squares throughout Egypt to support the revolution. It appears the call was heeded, as numbers swelled in Tahrir, Alexandria, Suez and Mansoura. Dr Omar Ashour, visiting scholar at the Brookings Doha Center in Qatar, told msnbc.com the clearing of the security generals by the court sent "a message of impunity." This is highly problematic, as the verdicts empower an anti-reform, anti-revolution dominant faction in interior ministry. Tahrir Square will challenge this outcome. We just got out of election where more than 15 million voted for pro-change, not pro-status-quo, candidates.