Downtown Cairo has erupted in massive clashes as police attacked demonstrators near the iconic Tahrir Square on Friday afternoon with tens of thousands of Egyptians took to the square to demand the end of President Mohamed Morsi's regime. Police have used a large number of tear gas in an effort to disperse protesters, who remain determined to stay in the square and protect those behind them on the frontlines of the violence on Qasr el-Aini street. Bikyamasr.com staff was on hand as the first barrage of protesters were being attacked by police, including hundreds of black clad police in full riot gear chasing after the protesters. Below are some photos from the day's events.