US Secretary of State Hillary Clinton today accused North Korea of a campaign of provocation as the Asia-Pacific security forum descended into recriminations over tensions on the Korean peninsula. In her prepared remarks to the foreign ministers gathered at the region's biggest security dialogue in Hanoi, Mrs. Clinton said an isolated North Korea has embarked on a campaign of provocative, dangerous behavior. She said peaceful resolution of the issues on the Korean peninsula will be possible only if North Korea fundamentally changes its behaviour. Earlier, North Korea has vowed a physical response to new US sanctions and condemned massive US-South Korean naval exercises due to begin Sunday in the Sea of Japan as gunboat diplomacy.