HYDERABAD: 55th Andhra Pradesh Formation Day was marred by massive protests by pro-Telangana organizations and attack on the houses of ministers and other Congress leaders across the region Monday. While a colorful official function, sans much public was held in Hyderabad amid tight security, protestors had a field day across the region that hoisted black flags in universities, government offices and even police stations. The activists of Osmania University Students Joint Action Committee, Political Joint Action Committee and Telangana Rashtra Samiti organized demonstrations, took out rallies and tried to block the path of the convoy of the Chief Minister K Rosaiah when he was on his way to participate in the official celebrations. Police used force and arrested 50 students when they gathered near the residence of the Chief Minister in the morning and tried to stop his convoy. In the University Campus, where police and Rapid Action Force were deployed, the students hoisted black flag and took out a massive rally shouting slogans in support of Telangana state. A mob attacked the residences of minister for tourism and information Dr J Geeta Reddy and Congress MLA Marri Shashidhar Reddy damaging the window panes and other property. They also burnt the posters and cutouts of Geeta Reddy in protest against her decision to participate in the celebrations. Police arrested six student leaders from Osmania University in connection with the attack on Shashidhar Reddy's residence in Tarnaka and they were sent to judicial custody for a week. TJAC convenor Prof Kodanda Ram along with other supporters was arrested by the police when he held a dharna on the high way at Hayatnagar.