ANDORRA (REUTERS) - United Nations Secretary-General Ban Ki-moon said on Tuesday that a crisis over North Korea had gone too far and urged dialogue and negotiation to resolve the situation.

"Nuclear threats are not a game. Aggressive rhetoric and military posturing only result in counter-actions, and fuel fear and instability," Ban said at a news conference in Andorra, where he was on an official visit.

Earlier on Tuesday, North Korea's leader appeared to tamp down hostile rhetoric that had threatened impending war with the United States and South Korea.

The US has bolstered its forces in the region after a series of threats by Pyongyang to attack US bases in the Pacific and to invade South Korea.

"Things must calm down, as this situation, made worse by the lack of communication, could lead down a path that nobody should want to follow," Ban said, offering to help the parties to begin talks.

"I am convinced that nobody intends to attack (North Korea) because of disagreements about its political system or foreign policy. However, I am afraid that others will respond firmly to any direct military provocation," he said.

He also called on North Korean authorities to abide by resolutions from the United Nations Security Council.