( L - R ) Bush, Annan and Hu

WASHINGTON (AP):

President George W. Bush called yesterday for stiff sanctions on North Korea and stressed Washington had no intention of attacking the reclusive regime, even as Pyongyang warned of possible military reprisals if the United States did not stop "pestering" it about its claimed nuclear test.

Rejected meetings

Bush also rejected direct meetings with the North, just minutes after United Nations Secretary-General Kofi Annan called on the United States to hold bilateral talks with North Korea to ease deepening tensions.

U.S. officials said they hoped to circulate a revised U.N. resolution calling for sanctions on North Korea.

Meanwhile, Washington's partners in stalled North Korean nuclear negotiations took action on their own. Japan issued a volley of its own tough sanctions. China sent a special envoy for President Hu Jintao to Washington for talks.

And South Korea said it was making sure its troops were prepared for atomic warfare and may bolster its conventional forces as well. The top U.S. general in South Korea also said American soldiers were poised to repel any attack.

Amid the deepening unease, North Korea lashed out with threats of more nuclear tests and warned that U.N. sanctions would be tantamount to a declaration of war.

Annan urged North Korea not to escalate an "extremely difficult" situation.

In a White House news conference, Bush said the United States remains committed to diplomacy but also "reserves all options to defend our friends in the region."

North Korea has said that one reason it tested an atomic weapon is fear of attack from the United States.

But Bush said the United States has "affirmed that we have no nuclear weapons on the Korean Peninsula. We affirmed that we have no intention of attacking North Korea."

Diplomatic measures

In answer to a question he asked himself - why the U.S. does not take military action against North Korea - Bush said: "I believe the Commander in Chief must try all diplomatic measures before we commit our military."

North Korea, in its first formal statement since Monday's claimed bomb test, hailed the blast as a success and said attempts by the outside world to penalise North Korea with sanctions would be considered an act of war.

Further pressure will be countered with physical retaliation, the North's Foreign Ministry warned in a statement carried by the official Korean Central News Agency.

"If the U.S. keeps pestering us and increases pressure, we will regard it as a declaration of war and will take a series of physical corresponding measures," the statement said, without specifying what those measures could be.

Unfazed by the threats, Japan announced a crackdown meant to hit the economic lifeline to the North's 1-million-member military, the world's fifth largest.

The new measures ban North Korean imports and prohibit ships from the impoverished nation from entering Japanese ports. North Korean nationals will also be barred from entering Japan, with limited exceptions, the Cabinet Office said after an emergency meeting.

"Japan is in gravest danger, if we consider that North Korea has advanced both its missile and nuclear capabilities," Prime Minister Shinzo Abe told reporters following the meeting. "These measures were taken to protect the peace."

A ban on imports and ships would be a blow to North Korea, whose produce like clams and mushrooms earns precious foreign currency on the Japanese market. Ferries have long served as a major conduit of communication and cash between the two countries, which have no diplomatic relations.

Japan stepped up sanctions even before the U.N. Security Council finished debating a U.S.-backed proposal that would further punish the North.

Washington has asked the council to impose a partial trade embargo including strict limits on North Korea's weapons exports and freezing related financial assets. All goods sent to North Korea would be inspected too, to filter materials that could be made into nuclear, chemical or biological weapons.

North Korea's No. 2 leader Kim Yong Nam threatened in an interview with a Japanese news agency that there would also be more nuclear tests if Washington continued what he called its "hostile attitude."

"The issue of future nuclear tests is linked to U.S. policy toward our country," Kim Yong Nam was quoted as saying by Kyodo News agency when asked if Pyongyang will conduct more tests.

Along the razor-wired no-man's-land separating the divided Koreas, communist troops were more boldly trying to provoke their southern counterparts: spitting across the demarcation line, making throat-slashing hand gestures, flashing their middle finger and trying to talk to the troops, said U.S. Army Maj. Jose DeVarona, adding that the overall situation was calm.

On the streets of North Korea's capital, it seemed like business as usual. Video by AP Television News showed people milling about Kim II Sung square in Pyongyang and rehearsing a performance for the 80th anniversary of the "Down with Imperialism Union."

South Korean Defence Minister Yoon Kwang-ung said Seoul could enlarge its conventional arsenal to deal with a potentially nuclear-armed North Korea.

In rare direct criticism of the communist regime from Seoul, South Korean President Roh Moo-hyun said the security threat cited by North Korea "either does not exist in reality, or is very exaggerated," according to South Korea's Yonhap news agency.

He spoke even as South Korea's military was checking its readiness for nuclear attack, Yonhap said. The Joint Chiefs of Staff recommended improving the military's defences, possibly with state-of-the-art weapons to destroy nuclear missiles, the report said.