John Bacon

USA TODAY

North Korea is "begging for war," and the United Nations must exhaust all diplomatic means to halt the expansion of the North's nuclear program before it's too late, U.S. Ambassador Nikki Haley told an emergency meeting of the Security Council on Monday.

"Enough is enough," Haley said, one day after North Korea's sixth and by far most powerful nuclear test. "We have kicked the can down the road long enough. There is no more road left."

Haley's remarks come as Japan is reportedly planning for a possible mass evacuation of nearly 60,000 of its citizens in South Korea as tensions with North Korea continue to rise, FOX News reported Monday. The Japanese citizens in South Korea are either living in the country or are visiting.

"There is a possibility of further provocations," Japanese Prime Minister Shinzo Abe said, according to Japanese magazine Nikkei Asian Review. "We need to remain extremely vigilant and do everything we can to ensure the safety of our people."

Haley said the U.S. would be circulating a proposal for new, tougher sanctions, and she dismissed "freeze for freeze" proposals from China and Russia. Those nations are calling for North Korea to halt nuclear development in exchange for a halt in U.S.-South Korean joint military exercises and removal of a U.S. anti-missile system from the peninsula.

Haley also sounded a recurring theme from the Trump administration that China must use its sway with North Korean leader Kim Jong Un to halt his nuclear program. About 90% of North Korea's foreign trade is conducted with China.

"The United States will look at every country that does business with North Korea as a country that is giving aid to ... reckless and dangerous nuclear ambitions," Haley said.

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The U.N. has enacted a series of harsh economic sanctions over more than two decades that have left North Korea as one of the world's poorest nations, yet have failed to halt Pyongyang's drive to join the nuclear community. Russia and China have expressed doubt that additional sanctions will move the needle with Kim.

On Sunday, North Korea conducted its sixth nuclear test and first in almost a year. Pyongyang claimed it tested a miniaturized hydrogen bomb that could be transported on a ballistic missile. Details could not immediately be verified, but South Korean officials estimated the blast had a strength of 50 to 100 kilotons — markedly more powerful than previous tests or the bombs dropped by the U.S. on two Japanese cities in World War II.

South Korea responded Monday, firing a ground-to-ground ballistic missile and a long-range, air-to-ground missile from an F-15K fighter at targets in the Sea of Japan, the military said. The simulated targets were designed to replicate the location of the North's Punggye-ri nuclear test site.

Defense Minister Song Young-moo told a South Korean parliamentary session that the country's leadership is leaning in "a direction that strengthens the military standoff, rather than ... dialogue."

The simulation came as South Korea's National Intelligence Service warned its nation's lawmakers that North Korea may be preparing to test another intercontinental ballistic missile, South Korea's Yonhap news agency reported. The spy agency, in a closed session, warned that the test could be tied to the anniversary of the regime's founding set for Saturday or the anniversary of the establishment of the ruling Workers' Party of Korea on Oct. 10.

North Korea flew a missile over northern Japan last week, the first such overflight by a missile capable of carrying nuclear weaponry. North Korean leader Kim Jong Un described that missile test as a “meaningful prelude” to containing Guam, home of major U.S. military facilities.

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Sunday's nuclear test prompted a chorus of global condemnation and drew an angry response from the Trump administration. Defense Secretary Jim Mattis warned of a "massive military response" against North Korea if the U.S. or its allies are threatened. Mattis added that "we are not looking to the total annihilation of a country, namely North Korea, but as I said we have many options to do so."

President Trump took to Twitter on Sunday, blasting Seoul for what he described as a policy of "appeasement" and threatening to cut off trade with China for failing to use its influence with Pyongyang to stop the nuclear buildup.

China issued a statement condemning Pyongyang's test but also termed Trump's threat "unacceptable." Geng Shuang, a Chinese Foreign Ministry spokesman, said China was working to resolve the issue of nuclearization of the Korean Peninsula and did not deserve to be the subject of sanctions.

Trump and South Korean President Moon Jae-in talked Monday for the first time since the nuclear test. The leaders agreed to increase the payload of South Korean missiles, Moon's office said. The chat came just days after reports that Trump was considering withdrawing from a trade agreement with Seoul.

Moon also has agreed expand the U.S.-provided Terminal High-Altitude Area Defense System (THAAD). That drew predictable outrage from the North, its state-run news agency asserting that "THAAD is not capable of deterring the merciless strike by the (North Korean military), fully determined to reduce to ashes the strongholds of aggression and destroy the provocateurs at a single strike."