N Korea vows to reduce South leadership to ashes

North Korea sharply escalated the rhetoric against its southern rival,claiming it will soon conduct “special actions’’ that would reduce South Korea’s conservative government to ashes within minutes.

Monday’s threat from the North’s military leadership comes amid concerns that North Korea may be plotting another provocation in the wake of an unsuccessful rocket launch condemned by the UN Security Council as a violation of a ban against missile activity.

UN Secretary-General Ban Ki-moon urged North Korea to refrain from “further provocative measures,’’ telling reporters in New York late Monday that such actions “will not be desirable for the peace and stability of the Korean peninsula.’’

North Korea characterized the April 13 rocket launch as a failed bid to send a satellite into space — not a disguised test of missile technology as Washington and Seoul claim. Two days after the attempt,Pyongyang unveiled a new long-range missile at a military birthday parade for late Kim Il Sung.

There are new concerns that North Korea may conduct a nuclear test as it did after rocket launches in 2006 and 2009. South Korean intelligence officials say satellite images show the North has been digging a new tunnel in what could be preparation for a third atomic test.

On the North Korean side of the Demilitarised Zone,a military guide told The Associated Press that he believes his country needs atomic weapons to defend itself against the threat of attack from the US.

“Nuclear weapons are not the monopoly of the US,’’ Lt. Col. Nam Dong Ho said. “It’s my personal opinion,but I think we’ll continue to conduct nuclear tests.’’

A South Korean Defence Ministry official said no special military movement had been observed in the North. There also was no outward sign of tension on the North Korean side of the Demilitarized Zone.