Guwahati, April 20 : Two suspected cattle smugglers from Uttar Pradesh were killed during an ambush on a police vehicle by unidentified extremists in Assams Kokrajhar district on Tuesday. The militants were reportedly trying to free the smugglers who were a source of funding for them, the police said. According to the police, the militants attacked their vehicle at Jamduar when the two arrested cattle smugglers -- Akbar Banjara and Salman Banjara -- were being taken to the Sankosh river along the border with Bhutan for the identification of cattle smuggling routes. They were arrested from Meerut in Uttar Pradesh for their alleged involvement in an international cattle smuggling racket. During the encounter between the police and the extremists, Akbar, Salman and four police personnel sustained bullet injuries. After the gun-battle stopped, the police took the injured smugglers to a nearby primary health centre, where the doctors declared them brought dead. The roads were blocked with felled trees at the incident site. The police later recovered an AK-47 rifle along with two magazines, 35 rounds of live ammunition and 28 rounds of empty shells. "During interrogation, the duo had elaborated the modus operandi of cattle smuggling from Uttar Pradesh, Haryana and West Bengal to Bangladesh via Assam. The smugglers provide huge sums of money from their illegal trade to the militant outfits in the Bodoland Territorial Region," an official said. Militant outfits in Assam and Meghalaya are the main beneficiaries of this clandestine nexus. This is the first such instance of alleged cattle smugglers dying in police custody. /IANS