National Security Advisor M K Narayanan has said that a far more intensive exchange of information and intelligence is needed among nations on the issue of nuclear security. Addressing the Plenary Session of Manama Security Conference in Bahrain, he said that strict and adequate preventive measures are vital as the possibility of terrorists gaining access to nuclear materials and technologies and the shadow of nuclear terrorism is perhaps the gravest threat to global security and mankind at this moment. Mr. Narayanan said that energy is vital for India as this is the engine of country’s economic growth, which has averaged 7 to 9 per cent during the last decade.<br/>