NEW DELHI: Contrary to the government's claims that there has been no largescale illegal migration from Bangladesh in recent years, Army chief general Bikram Singh on Tuesday called it a matter of "grave concern" and a threat to national security.

"The problem of illegal migration in Bangladesh has led to demographic changes in the northeast. It has led to serious internal security challenges in Assam," Singh told a seminar on "Border and Naxal Management", organised by a security think tank. He said the forces had received a lot of help from the current political dispensation in Bangladesh but responsibility needed to be fixed on illegal migration.

Singh also came down heavily on Pakistan for keeping the western border on fire by indulging in record ceasefire violations last year and blamed it on Islamabad's agenda to foment terrorism in the Kashmir valley in order to maintain its military presence in border areas. "The 2003 ceasefire was holding good, but last year has seen an increase in violations. It is being done with an agenda to hype terror in the valley to maintain army presence...," the Army chief said adding that Indian army had given Pakistan a fitting reply.

"I don't want to sound jingoistic... But we have given Pakistan a bloody nose," Singh said. He warned that as long as the nexus between the state polity (in Pakistan) and terror outfits like LeT continued and it kept getting financial support in an institutional manner, the forces should be prepared for all eventualities.

Singh also raised the red flag over former militants from Kashmir returning to the Valley through Nepal under the state government's rehabilitation policy. He said many of them are suspected to indulge in forming sleeper cells for terror outfits. "Use of the Nepal route by former Kashmiri militants to come back to the valley is a cause for concern. Though it appears they have mellowed down, the fear is that they could form sleeper cells and carry out terror activities. We have to be careful," he said.

The Army chief also lamented partial implementation of recommenations of the group of ministers, formed in the wake of the Kargil Review Committee report in 2000. The panel had suggested various changes in the security apparatus including synergy of stake holders, dedicated resources for border management, enhancing of combat power of forces, synergy of various intelligence agencies and the mantra of "one border one force" which asked for all active borders to be under the operational control of the Army.