Cairo ( CNN ) -- Egypt sent hundreds of troops with armored vehicles onto the streets Wednesday to protect the Ministry of the Interior , the army taking over from the police , as anti-government protests raged . The confrontations began when a planned memorial for people killed in Egypt 's revolution earlier this year turned into an angry demonstration against the country 's interim military government . Clashes began Tuesday afternoon and continued overnight and into Wednesday , with intense confrontations between relatives of victims on one side and security forces on the other . Many Egyptians are angry at the slow pace of change since President Hosni Mubarak resigned on February 11 after protests . A group called the January 25 coalition issued a range of demands Wednesday night , a day after the demonstrations began . They called for the `` speedy trial of snipers and killers of protesters , the removal of Cairo 's head of security and the official spokesman of the Ministry of Interior '' and `` an immediate investigation in the events of last night . '' The group , named for the day anti-government protests began this year , also called for the release of detainees held overnight and the `` immediate expulsion of security officers who continue to butcher and kill Egyptian people , '' among other demands . Protesters burned tires and threw Molotov cocktails , and police responded with tear gas , bullets and pellets in the biggest demonstrations in Cairo in months . But despite the efforts of police , demonstrators maintained their positions in Cairo 's Tahrir Square , increasing their numbers to about 2,000 . Dr. Hatem Ashraf , the minister of health , said 75 people were admitted to hospitals , with 10 still there after 65 people were treated and released . Ministry spokesman Dr. Adel Al Adawy said earlier that 32 police officers were injured and more than 590 people were treated at the scene of the clashes . Some 23 ambulances were running to help care for the wounded , he said . Nine people were arrested , said Alla Mahmoud , a spokesman for the Ministry of Interior . `` Thugs carrying swords and weapons infiltrated the protesters and attacked the Ministry of Interior with Molotov cocktails and rocks , '' Mahmoud said . A makeshift clinic was established in a nearby mosque where dozens of people were treated for minor wounds and fatigue from inhaling tear gas . Many people were seen bleeding from their heads and had suffered bullet wounds to the chest and face . Several thousand protesters chanted against Gen. Mohamed Hussein Tantawi , who heads the Supreme Council of the Egyptian Armed Forces . The council has been running the country since Mubarak was forced to step down . The council said the demonstrations `` have no excuse but to destabilize the security and stability of Egypt . '' The armed forces statement urged `` the great Egyptian people ... not to follow these calls ... for the sake of the security and safety of Egypt in these difficult circumstances . '' Ambulances streamed out of the square in the aftermath , transporting protesters to hospitals , while others were treated on the scene . Noor Noor , the son of presidential candidate Ayman Noor , was seen bleeding with a serious injury to his eye and was later transferred to the hospital . The protesters blocked the entrances to the square as calls were made on the Internet for more people to join the cause . The imam of the nearby Omar Makram Mosque called via loud speaker for police to stop attacking the protesters , saying Tahrir Square belonged to `` the revolutionaries . '' He also urged the demonstrators to go home . By late afternoon Wednesday , the square that was the center of the revolution was no longer blocked , but demonstrators remained at the Interior Ministry , the focus of much of the anger . The human rights group Amnesty International has estimated at least 840 people were killed and more than 6,000 wounded during the 18-day revolution that began in late January . The military-led government that took over when Mubarak resigned has been prosecuting several former officials accused of ordering security forces to fire on protesters . A police officer accused of killing 20 protesters during a January 28 demonstration has been sentenced to death . Former Interior Minister Habib El Adly has been sentenced to 12 years for corruption charges but still awaits the verdict for the charge of killing protesters . Mubarak is scheduled to face the Cairo Criminal Court on August 3 on charges of corruption and deaths of protesters , the justice department said Wednesday . Egypt 's military rulers have set parliamentary elections for September . Protests have continued in the months since Mubarak 's ouster as Egyptians have demanded speedier reforms and economic improvements . CNN 's Amir Ahmed and Journalist Hamdi Alkhshali contributed to this report .
NEW : An opposition group demands that officials be sacked over the crackdown . Hundreds of people are treated at the scene and dozens end up in hospitals . Police use tear gas and rubber bullets against protesters . Tahrir Square was the heart of the revolt against then-President Hosni Mubarak .