New Delhi: Terming internal security as a "critical" matter, India on Sunday expressed concern over increased infiltration attempts from Pakistan recently and said these threats shall be overcome "at all costs" with a coordinated efforts between the Centre and states. Inaugurating the Chief Ministers Conference on Internal Security, Prime Minister Manmohan Singh said, "Hostile groups and elements operate from across the border to perpetrate terrorist acts in the country. The state of Jammu and Kashmir bears the brunt of the acts of these groups."