North Korea is trying to develop small nuclear weapons that can be delivered by missiles or aircraft, South Korea's Defence Minister said on Tuesday.
Kim Tae-Young told lawmakers the North is "constantly seeking to make its nuclear weapons smaller" for possible future delivery by ballistic missiles or bombers.
Kim said the North is also believed to have 40 kg of bomb-making plutonium, slightly less than previous estimates by the United States. He said it is "quite possible" that Pyongyang is also building nuclear weapons through uranium enrichment in addition to its plutonium operation.
"The more you test the weapons, the more likely you will deploy them to the field," he said. The North quit multinational nuclear disarmament talks in April 2009 and conducted its second nuclear test a month later.
But Kim said he sees "no clear signs" so far that the communist country is preparing for another test. Kim said last month that Pyongyang is restoring facilities at its Yongbyon nuclear reactor, its source of weapons-grade plutonium in the past.
Kim Tae-Hyo, the president's deputy national security adviser, also said last month that the nuclear programme could cause immense damage in South Korea if Pyongyang develops smaller mobile weapons.
The North's current plutonium stockpile is estimated to be enough for six to eight bombs.