A researcher argued Friday that North Korea is developing nuclear weapons not to use in war, but as a means to press for a peaceful reunification with the South on its own terms.

"In its nuclear strategy, North Korea aims to achieve unification with South Korea by keeping the US from getting involved and without going to war against the South," Lee Choon-kun of the Korea Institute for Maritime Strategy said in a forum in Seoul.

Pyongyang is developing nuclear-tipped missiles capable of reaching the US mainland to prevent any intervention by the US on Korean issues, he argued.

"Nuclear weapons being developed by the North are not aimed at striking the US," he said in the conference arranged by the Citizens United for Better Society, a conservative nonprofit organization.

Assessing that South Korea's policies toward the North's nuclear program have not been successful, the researcher said the country is not yet ready to counter the communist state's evolving nuclear threats.

He pushed for Seoul's own nuclear armament as an effective deterrent against Pyongyang's weapons of mass destruction.

Pyongyang conducted its fourth and fifth nuclear tests in January and September along with more than 20 missile tests this year alone. (Yonhap)