Six persons, including four security personnel were killed by armed Maoists in separate incidents in Orissa, Bihar and West Bengal in fresh attacks today. <br/><br/>The Maoists blew up a government toll plaza in Gaya district in Bihar using dynamites and looted 16 weapons. Two persons including a security guard and a truck driver were killed in the attack.<br/> <br/>In Orissa, three security personnel were killed and six injured, four of them critically, in a fierce encounter with Maoists in Gajapati district early today. Acting on a tip-off about the movement of ultras, a team of security personnel including the elite anti-naxal Special Operation Group and state police launched a combing operation in Ambajari forest in the wee hours.<br/> <br/>In another incident in the nearby Malkangiri district, about 50 armed ultras blew up a pump house and control room near the pipeline of a private industrial house meant for movement of minerals. The ultras raided the area in the early hours and triggered the explosion after overpowering the guards.<br/> <br/>In West Bengal, Maoists killed a CPI(M) activist, after abducting him from home in West Midnapore district. His bullet-riddled body was recovered from the area today.<br/><br/>The violence occured as the Maoist' 48-hour bandh in seven states to protest against the Government's operations against Naxals drew to a close.<br/><br/>Meanwhile, two day bandh call given by Maoists in Orissa in protest of ‘Operation Green Hunt’ turned violent today when Maoists struck at a security team killing three SOG jawans and grieviously injuring four others. Gajapati District Superintendent of Police Mr Sanjeev Arora said acting on a tip off a joint team of SOG & State Police had ventured into the dense jungles near Ambagiri village in the suburb of Paralakhemundi town of Gajapati district midnight. Suddenly at about 2.30 A.M. a group of rebels began firing at the security personnel. In the ensuing exchange of fire, three SOG jawans lost their lives and four others were injured. A massive hunt has begun in the jungle by the police to nab the culprits, said Arora. <br/><br/>In another development a group of Maoists attacked a Special Police Officer who was visiting his village to attend a festival, another villager was also injured in the mella. The officer has been shifted to a hospital in Vyzag for emergency operation.Later in the day, the red revels struck again at Chitrokonda reservoir of Malkangiri by burning a pump house of a private power company.