( CNN ) -- Dozens of demonstrators demanding the revocation of a new protest law clashed with Egyptian security forces in Cairo Tuesday , igniting a firestorm of criticism online and on the streets , state media and activist reported . Police fired water cannon and tear gas canisters to disperse two small demonstrations , one against the military trials of civilians and another in honor of a man killed by police last year . `` Riot police began pulling and pushing everybody , beating us with sticks , grabbing hair , and dragging people . Immediately afterwards , tear gas was fired . I actually could n't breathe because the gas was so intense . I started running and I saw some people were being arrested , '' activist Gigi Ibrahim told CNN as she described how nearly 200 riot gear clad police officers broke up a demonstration she attended that had around 100 people . Prominent youth activists refused to abandon colleagues detained by the security forces and instead voluntarily surrendered to authorities in a show of solidarity . The group included founders of the group No to Military Trials , journalists , and a human rights lawyer . `` People gathered in front of the Shura Council in central Cairo in violation of the protest law . The security apparatus immediately issued a warning to demonstrators but they did not comply and threw rocks and bricks at the police . '' an Interior Ministry statement said , adding that 28 people were detained . Police later dumped more than a dozen of the female detainees along an empty highway after beating and harassing the group for several hours , several witnesses and activists reported Tuesday . `` We were thrown in the desert , our friends found us and we are all ok. F*** scaf ( Supreme Council of the Armed Forces ) and f*** the police , '' Salma Saed , one of the activists arrested , tweeted upon her release . The crackdown on some of Egypt 's most recognizable dissident figures comes just one day after the military-backed government announced the implementation of a new protest law that requires organizers seek permission from authorities before gathering . `` If the police and the government are not getting this message , we can protest every day for the rest of our lives because there are so many people who gave their lives for the right to protest . We gained this right to protest so there is no way we can go back . It is impossible . '' Ibrahim said .
Egyptian police use water cannon , tear gas to disperse two demonstrations . Some youth activists surrender to show solidarity with colleagues . - March 15 : Some female detainees abandoned on a highway , witnesses , activists say .