NEW DELHI (Agencies) - Indian Prime Minister Manmohan Singh on Friday called for an upgrade of the countrys defence doctrine, warning of the growing threat posed by militant groups with access to the latest technology. The Indian Premier also said that Naxalism and Left wing extremism posed the greatest threats to national security and the state cannot and will not allow its authority to be challenged. Non-state actors are becoming increasingly fused and employing the best technologies to target open and democratic societies like ours, Manmohan Singh told a seminar on the 'Role of Force in Strategic Affairs. We have to therefore modernise our defence doctrines to respond to new and non-traditional threats to our security, he said. Terrorist groups enjoy patronage and sanctuaries and do not lack in resources, Manmohan warned, stressing the need to maintain a logistical advantage over any groups planning to stage attacks on Indian soil or assets. We will ensure that our capabilities to combat terrorism remain a step ahead of those of the terrorists (and) they should be left in no doubt about our ability and resolve to defeat them, he said. Meanwhile, Indian Home Minister P Chidambaram said India could go more than half way to have better ties with Pakistan as things improve, and pitched for consolidation of trade between the two countries. As things improve we could go more than half way to have better relations with Pakistan. Trade must resume with Pakistan. I sincerely hope it will come sooner than later, he said. Speaking in Indian city of Hussainiwala, Chidambaram said people living in border areas 'carry with them a special burden and responsibility.