India's Prime Minister Manmohan Singh (top, 2nd L) disembarks his plane upon his arrival at the air base in Seoul March 24, 2012. Leaders from more than 50 countries will gather in Seoul for a March 26-27 nuclear security summit focusing on measures to protect nuclear materials and facilities and to prevent illicit trafficking. [Photo/Agencies]

NEW DELHI - Indian Prime Minister Manmohan Singh Saturday said that nuclear terrorism is a big threat to nations and reiterated his country's support for a world free from atomic weapons.

"This remains a continuing concern," Singh said in a statement as he embarked on a four-day visit to South Korea to attend the Nuclear Security Summit in Seoul.

Singh also said that in order to retain public support for harnessing the benefits of nuclear energy, the country must be able to assure them of the highest levels of nuclear security and safety.

This, the Prime Minister said, is "even more important" in the wake of the Fukushima nuclear accident in Japan last year.

India's Prime Minister Manmohan Singh (C) and his wife Gursharan Kaur (L) walk down the red carpet upon their arrival at the air base in Seoul March 24, 2012. [Photo/Agencies]