Maoists today blew up a bus killing at least 40 persons, including several Special Police Officers, in Dantewada district of Chhattisgarh. <br/><br/>The Naxals attacked the bus carrying passengers from Gadiras to Bhusaras in Dantewada district, nearly 400 Kilometers from Raipur, using Improvised Explosive Device this afternoon. <br/><br/>Official sources said, the SPOs, who are civilians assisting police in fighting the Naxals, were attached to Dantewada police. <br/><br/>The IED was planted on a metalled road and detonated by the Left-Wing Extremists using remote control device. <br/><br/>The attack came a day before the Maoists' call for a 48-hour bandh in five states, including Chhattisgarh, from tomorrow in protest against the security operations launched against them by the Centre. <br/><br/>The attack comes nearly a month after the Maoists gunned down 75 security personnel in Dantewada district in a deadliest ever attack on security forces. <br/><br/>Early reports say that a civilian bus was targeted in a landmine blast that took place this evening. <br/><br/>The bus was on its way from Sukma to Dantewada. The victims included Special Police Officers.<br/> <br/>The attack comes nearly a month after the Maoists gunned down 75 security personnel in Dantewada district in a deadliest attack on security forces. <br/>The centre has strongly condemned the naxal attack on a civilian bus in Chattisgarh today. <br/><br/>According to an official spokesman most of those killed were civilians. There was no CRPF personnel in the bus.