Cambodia arrests opposition leader, alleging treason

If quake was indeed the result of a nuclear test, its magnitude indicates it may have been North Korea's most powerful detonation yet. That could mean a significant step forward in the North's quest for a viable nuclear missile capable of striking anywhere in the United States.

South Korea's weather agency and the Joint Chiefs of Staff said an artificial 5.7 magnitude quake occurred at 12:29 p.m. local time, in Kilju, northern Hamgyong province, the site where North Korea has conducted nuclear tests in the past. Seoul officials revised their earlier estimate of 5.6 magnitude quake. The U.S. Geological Survey called the first quake an explosion with a magnitude 6.3.

The U.S. State Department had no immediate reaction. South Korea's presidential office said it will hold a National Security Council meeting chaired by President Moon Jae-in. South Korea's military said it has strengthened its monitoring and readiness while mulling a variety of possible responses that could be executed in collaboration with the U.S.

Japan confirmed that North Korea conducted a nuclear test, Foreign Minister Taro Kono said. "It is absolutely unacceptable if North Korea did force another nuclear test, and we must protest strongly," Prime Minister Shinzo Abe sai d.

China's earthquake administration detected a second tremor of magnitude 4.6 in North Korea minutes after the first. It described the event as a cave-in. South Korea's weather agency, however, said no second quake occurred.

North Korea conducted two nuclear tests last year, the last nearly a year ago, on the Sept. 9 anniversary of the nation's founding. It has since maintained a torrid pace in weapons tests, including its first two intercontinental ballistic missiles test in July. Last month, North Korea fired a potentially nuclear-capable midrange missile over northern Japan.

Earlier Sunday, photos released by the North Korean government showed Kim talking with his lieutenants as he observed a silver, peanut-shaped device that was apparently the purported thermonuclear weapon destined for an ICBM. What appeared to be the nose cone of a missile could also be seen near the alleged bomb in one picture, which could not be independently verified and was taken without outside journalists present. Another photo showed a diagram on the wall behind Kim of a bomb mounted inside a cone.

State media said Kim visited the Nuclear Weapons Institute and inspected a "homemade" H-bomb with "super explosive power" that "is adjustable from tens (of) kiloton to hundreds (of) kiloton."

North Korea's nuclear and missile program has made huge strides since Kim rose to power following his father's death in late 2011. The North followed its two tests of Hwasong14 ICBMs by threatening in August to launch a salvo of its Hwasong-12 intermediate range missiles toward the U.S. Pacific island territory of Guam.

It flew a Hwasong-12 over northern Japan last week, the first such overflight by a missile capable of carrying nukes, in a launch Kim described as a "meaningful prelude" to containing Guam, the home of major U.S. military facilities, and more ballistic missile tests targeting the Paci f i c.

It was not immediately known whether the nuclear device apparently set Sunday was an H-bomb.

Vipin Narang, a Massachusetts Institute of Technology professor specializing in nuclear strategy, said before the earthquake that it's important to note that the photos showed only a mockup of a twostage thermonuclear device, or H-bomb. "We won't know what they have until they test it, and even then there may be a great deal of uncertainty depending on the yield and seismic signature and any isotopes we can detect after a test," he said.

To back up its claims to nuclear mastery, such tests are vital. The first of its two atomic tests last year involved what Pyongyang claimed was a sophisticated hydrogen bomb; the second it said was its most powerful atomic detonation ever.

It is almost impossible to independently confirm North Korean statements about its highly secret weapons program. South Korean government officials said the estimated explosive yield of last year's first test was much smaller than what even a failed hydrogen bomb detonation would produce. There was speculation that North Korea might have detonated a boosted fission bomb, a weapon considered halfway between an atomic bomb and an H-bomb.

It is clear, however, that each new missile and nuclear test gives the North invaluable information that allows big jumps in capability. A key question is how far North Korea has gotten in efforts to consistently shrink down nuclear warheads so they can fit on long-range missiles.

"Though we cannot verify the claim, (North Korea) wants us to believe that it can launch a thermonuclear strike now, if it is attacked," said Adam Mount, a senior fellow at the Center for American Progress. "Importantly, (North Korea) will also want to test this warhead, probably at a larger yield, to demonstrate this capability."

North Korea is thought to have a growing arsenal of nuclear bombs and has spent decades trying to perfect a multistage, longrange missile to eventually carry smaller versions of those bombs.

South Korea's main spy agency has previously asserted that it does not think Pyongyang currently has the ability to develop miniaturized nuclear weapons that can be mounted on long-range ballistic missiles. Some experts disagree.

The White House said President Donald Trump spoke with Prime Minister Shinzo Abe of Japan regarding "ongoing efforts to maximize pressure on North Korea." The statement did not say whether the conversation came before or after the North's latest claim. PHNOM

PENH, Cambodia (AP) -- Cambodian authorities arrested the leader of the main opposition party on Sunday, accusing him of treason in a move that sharply escalated political tensions in the Southeast Asian nation ahead of national elections next year. His party denied the allegations and said the charges were politically motivated.

The arrest of Kem Sokha during a midnight raid on his Phnom Penh home appeared to be part of a broader push by the government of Prime Minister Hun Sen, one of the world's longest serving rulers, to crush opponents and silence critics ahead of the vote.

The government in recent weeks has closed down radio stations that gave air-time to the opposition party and threatened to shut down other independent media outlets on charges of violating tax laws that analysts say are politically motivated.

Kem Sokha was taken away in handcuffs after a force of between 100 to 200 officers swept his home, according his daughter, Monovithya Kem, who is also a member of his embattled Cambodia National Rescue Par t y.

Monovithya Kem said on Twitter that police showed no warrant for her father's arrest. She said later that his whereabouts were unknown. But Interior Ministry spokesman Gen. Khieu Sopheak said Kem Sokha was being held at the Tropeang Phlong prison facility in Tbuong Khmum province, some 130 kilometers (80 miles) east of Phnom Penh.

He said the next step will be his court appearance to officially face the charges, which carry a prison sentence of 15 to 30 year s.

The government said it had obtained a video clip and other evidence indicating "secret plans of a conspiracy between Kem Sokha ... and foreigners to harm the Kingdom of Cambodia."

The statement gave no details but called the actions "treason." Khieu Sopheak said that Kem Sokha had admitted in the video that "he was trained and received funding from a powerful foreign country to topple the government."

"This is a clear crime and there's no need to make further investigation because he has confessed already," he added.

Mu Sochua, a vice-president of the opposition party, insisted the charges were fabricat ed .

She also said that police could not legally arrest Kem Sokha, who as a lawmaker is entitled to parliamentary immunity. The arrest violated the constitution, she told The Associated Press, but "this government has not cared about the law in quite some time."

The arrest "sends a very clear signal that democracy in Cambodia is under severe threat," she said, adding that if Kem Sokha it is not released, "it's very clear there will be no free and fair elections" in 2018.

Analysts say the government of Hun Sen, an authoritarian leader who held a tight grip on Cambodia for more than three decades, has grown increasingly concerned about steady opposition gains at the ballot box over the last decade, including local elections held in June.

Legal threats forced Kem Sokha's predecessor, Sam Rainsy, to resign this year from the Cambodia National Rescue Party he once led. He now lives in exile.

John Sifton, Asia advocacy director at Human Rights Watch, said the arrest was "an extremely disturbing development and a setback for democracy in Cambodia."

"The government's charges lack credibility, given its long record of misusing its legal system to silence or intimidate critics and political opponents," Sifton said.