CAIRO: Egypt's Muslim Brotherhood supporters attacked a field hospital set up in the Roxy area of Heliopolis that was treating wounded protesters as clashes continue into Wednesday evening. “Anyone in Roxy pls tweet at me. An injured co-volunteer at FH there needs help. Head injury, says MB have overrun the Field Hospital,” wrote one witness on the micro-blogging site Twitter. The attack has shocked activists, as field hospitals have always been a safe haven from attacks, save by the police in previous violence that has erupted in the country over the past two years. “This is shocking and shows they are there to attack and kill,” said another activist in a brief phone conversation with Bikyamasr.com near the area. Thousands of supporters of Egypt's President Mohamed Morsi violently attacked and threw out protesters who had gathered by the presidential palace on Wednesday, taking down their tents. Reports suggest at least one member of the opposition is in a coma after being brutally attacked by a Brotherhood supporter. The president's opponents had announced a sit-in on Tuesday against a constitutional decree issued by Morsi and a draft constitution written by an Islamist-dominated assembly. Clashes erupted between opponents and supporters earlier where they hurled stones at each other and chanted opposing slogans. The violence continues into Tuesday evening, in what activists have described to Bikyamasr.com as “sad," “shocking" and “unbelievable." The Brotherhood supporters were heard screaming “Allah Akbar" as they rushed forward in wave after wave of attack against the protesters against Morsi.