Two militants belonging to the anti-talk faction of the ULFA were killed when a powerful bomb they were planting on railway tracks to target long-distance trains exploded in Assam's Sibsagar district early today.Officials said that, ahead of the arrival of Dibrugarh-Kolkata Kamrup Express, the Delhi-bound Brahmaputra Mail and North East Express, the two militants were fixing the bomb on the tracks between Bojo and Langpotia under Charaido subdivision around 1:45 am when the bomb went off.The police have recovered two bodies of the suspected militants from the blast site.AIR correspondent reports, train movement between Guwahati and Upper Assam area has been affected following the explosion on the railway track.A portion of the railway track between Bhojo and Longpotia stations has been damaged following the blast.North East Frontier Railway sources said Army and security forces have cordoned off the blast site and train movement towards Upper Assam has been suspended until clearance by the security agencies.The railway tracks damaged are being repaired. Meanwhile, Security forces have been alerted across the state, particularly in bordering areas along Nagaland and Arunachal Pradesh following the incident.