BY Richard Sisk
DAILY NEWS WASHINGTON BUREAU
North Korea took its nuclear brinkmanship up a notch Tuesday, threatening a military strike against the South after Seoul joined a U.S.-led initiative to intercept shipments suspected of being involved in weapons of mass destruction.
Pyongyang said it was no longer bound by the 1953 armistice that ended the Korean War.
A military statement quoted by official media also said the North could no longer guarantee the safety of shipping off its coast.
It repeated Pyongyang's position that Seoul's decision to join the international effort was tantamount to a declaration of war.
"Any tiny hostile acts against our republic, including the stopping and searching of our peaceful vessels...will face an immediate and strong military strike in response," the statement said.
"Our military will no longer be bound by the armistice accord as the current U.S. leadership ... has drawn the puppets [South Korea] into the PSI," said the statement, referring to the Proliferation Security Initiative.
The threat came as the U.S. looked to China to play the international heavy in cracking down on North Korea after the rogue nation's second missile test in as many days.
"China has an interest in what transpires for North Korea," said America's ambassador to the UN, Susan Rice.
"They share a border. They want to see a North Korea that's stable. On that, we are in full agreement," added Rice, who made the rounds on morning talk shows.
Rice insisted the U.S. and the international community have no intention of permitting North Korea to have a nuclear weapons program or export nuclear materials to other nations or rogue states.
A South Korean newspaper reported Wednesday that U.S. spy satellites have detected signs that North Korea has restarted a nuclear plant used to make bomb-grade plutonium.
To block Kim Jong Il's regime from shipping weapons technology to other rogue states, South Korea agreed Tuesday to join U.S.-led naval patrols in the region.
With the world growing increasingly weary of Pyongyang, Secretary of State Clinton phoned Russian Foreign Minister Sergei Lavrov to rally support for UN sanctions that would go beyond the hand-wringing expressions of concern in the past.
"At this time, we're working on a resolution, but I'm not going to prejudge how this is all going to come out with our partners," said State Department spokesman Ian Kelly.
In defiance of President Obama's warning that the allies would "take action," the North fired off three more short-range missile tests Tuesday, including one at night. That followed three missile launches Monday that came after an underground nuclear test of several kilotons Sunday.