Imphal Six men armed with sophisticated weapons attacked a group of construction workers in Manipur's Thoubal district on Thursday evening and escaped with Rs 2.30 lakh in cash, police said. The incident took place just half a km from the camp of Border Security Force. Combing operations launched on Thursday night failed to nab the culprits, police sources told IANS on Friday. Media reports said the armed men are suspected to belong a Nagaland-based outfit. Injured construction workers told IANS that the armed men raided the construction site of the mini barrage at Heirok in Thoubal. "Soon they started beating us up with wooden clubs. They asked for the whereabouts of the contractor", said a worker, who did not want to be identified. The beatings continued for a long time. The assailants ransacked the shack. They made away with Rs.2.30 lakh kept in cash for payment to the workers and purchase of construction materials. "They took away the money. Besides, they also snatched six mobile handsets from us and some domestic tourists who happened to be present there at that time", said another worker. There have been increasing reports of abductions of workers and bomb blasts in Tamenglong district where the tunneling and rail line construction works are going on. "Because of such disturbances there is inordinate delay in the construction works. Though behind schedule, we hope that the construction works of the rail line reaching the state capital shall be completed by February next year," Chief Minister Okram Ibobi Singh said.