NEW : 6 are dead and at least 300 injured , the Egyptian Health Ministry says . The attack happened in a busy shopping area of Cairo where many people were out for Friday night's fireworks celebrations. Glass , rocks and Molotov cocktails are thrown . The beating of an activist sparked the violence , activists say .
NEW : 6 are dead and at least 300 injured , the Egyptian Health Ministry says . An investigation is under way , a government spokesman says . Glass , rocks and Molotov cocktails are thrown . The beating of an activist sparked the violence , activists say .