North Korea stepped up threats over its controversial nuclear weapons programme on Tuesday, saying it would use the missiles if provoked.
In a commentary released by the state-run Minju Choson newspaper, North Korea raised tensions again in what is widely regarded as an attempt to stave off international punishment for its May 25 nuclear test.
North Korea's nuclear deterrent was a "powerful defensive measure to secure the peace and stability of the Korean Peninsula and nearby regions," the commentary said.
"It will become a vehicle for merciless attacks on those who even slightly infringe upon our sovereignty," it added.
Observers in South Korea regard the commentary a reminder of Pyongyang's threats to take "defensive measures" in case the international community punished the Stalinist state.
According to the South Korean Yonhap news agency, this is the first time North Korea has referred to using its nuclear arsenal in a military offensive.
The UN Security Council in New York is debating a resolution tightening sanctions against North Korea. After Pyongyang's first nuclear test in October 2007, the body had passed a series of sanctions against the country.
Wi Sung Lac, a South Korean negotiator in international talks on the North's nuclear weapons programme, said the Security Council members were about to reach agreement on a resolution. He expected this to be finalised on Wednesday or Thursday.