"Inimical forces, both inside and outside India, are trying to stunt growth and well-being of the country. The twin threats of terrorism and communalism must be defeated," Singh told NCC cadets at their Prime Minister's Rally here.
"In such circumstances the responsibility of youth organisations like NCC that inspires its cadets to serve the country increase manifold," he said after reviewing the NCC cadets' parade.
The Prime Minister said though the 13-lakh cadet strong NCC was a large organisation, it comprised of just about four per cent of the eligible youth in the country.
"I wish and urge you to increase this number so that many more eligible youth can benefit from the NCC's activities," he said.
Applauding the "disciplined and smart" turn out of the NCC cadets at the parade, Singh congratulated them on their achievements in activities like mountaineering and sports at the global level.
Recalling that India's first Prime Minister Jawaharlal Nehru had in 1952 directed inclusion of community development as a curriculum in NCC, the Prime Minister said he was happy to note that the cadets were actively involved in disaster relief and social service, apart from global warming, environment, cancer and AIDS relief.
He also called for expanding the scope of the youth exchange programme of the NCC to increase the number of cadets from foreign countries attending the camp.
Defence Minister A K Antony, Minister of State for Defence M M Pallam Raju, Army Chief Gen Deepak Kapoor, IAF Chief Air Chief Marshal P V Naik and Navy Chief Admiral Nirmal Verma were present on the occasion.
Singh also gave away awards to the winners of various trophies and medals at the camp held in connection with the 61st Republic Day Parade on January 26.
The Champion Directorate trophy for 2010 went to Maharashtra, while Punjab, Haryana, Himachal and Chandigarh Directorate was adjudged the runners up.
The Best Directorate for Girls Wing went to Tamil Nadu, the Best Directorate (Army) Trophy went to Kerala and the Navy and Air Wings trophies were won by Maharashtra.
There were nearly 100 cadets from countries like Sri Lanka, Russia and Kazakhstan who attended the parade and marched alongside the Indian NCC cadets.
The NCC also displayed the war-fighting training provided to them at the camp, including slithering operations and flying of micro-light aircraft and mass band.