TOKYO — Less than a week after North Korea test-launched four ballistic missiles that plunged into the Sea of Japan 200 miles from Japan, neighboring Asian nations are scrambling for a plan on how best to confront the defiant government of Kim Jong Un.

And that topic will be at the forefront this week as Secretary of State Rex Tillerson takes his first trip in office to Asia, a six-day sweep through Tokyo, Seoul and Beijing. He will be faced with a range of options that include opening a dialogue with North Korea, adding new sanctions or even launching a pre-emptive strike on North Korea’s facilities.

Yet the most perplexing issue for Tillerson could be how to navigate the fractious relationships the Asian nations have with one another. South Korea and Japan struggle with deep-rooted animosities that go back generations, while both complain that China shields North Korea from significant punishment.

“The Trump administration’s actions in this region will be vital to determining whether the North Korea situation improves or continues to deteriorate,” said Hideaki Kaneda, a retired Japanese vice admiral and fellow at the Japan Institute of International Affairs.

“It’s a very precarious situation,” he said. “The U.S. must try to bring together nations who are reluctant to put their faith in one another.”

The U.S. would like to see all three Asian nations join with Washington to confront North Korea, but the tangled relationships among them make that difficult.

Japan wants a more active U.S. response to North Korea and is working to put pressure on Pyongyang. But Japan and South Korea remain locked in a standoff over bitter memories of World War II, especially the treatment of thousands of Korean women who were forced into sexual slavery by Japanese occupation forces.

China remains North Korea’s only major ally and trading partner, but has stepped up economic pressure on Pyongyang in response to its nuclear tests. Relations between China and North Korea are at their worst in recent memory because of the repeated military tests. Yet the Chinese fear pushing too hard and then having to deal with a collapsed North Korea.

China has called on its neighbor to suspend its nuclear and missile activities in exchange for the U.S. and South Korea halting joint military exercises in South Korea. That offer fell flat. Washington refused to even consider what it said would be rewarding Pyongyang’s bad behavior with cancellation of legitimate defensive exercises.

Meanwhile, U.S. efforts to strengthen South Korea’s defenses have angered the Chinese, who say that planned anti-missile systems could be used against them.

Last week, the U.S. and South Korean militaries announced the deployment of elements of the Terminal High-Altitude Area Defense system, or THAAD, a missile-defense system for South Korea. Missile launchers and other equipment arrived in South Korea, but the system as a whole won’t be operational until April at earliest.

The U.S. insists THAAD is aimed at stopping North Korean missiles, but the deployment infuriated China, which sees the system as part of a U.S. strategy to contain its rising power. The Chinese have threatened to essentially sever diplomatic ties with Seoul and have already pulled back on economic ties.

Complicating matters further is the corruption scandal that led to South Korean President Park Geun-hye’s ouster Friday. The turmoil in South Korea’s government almost certainly will make it more difficult for Tillerson to gain traction with the country’s politicians.

For more than a decade, the complicated mix of interests in East Asia has stymied repeated U.S. efforts to block North Korea from slowly but steadily developing nuclear weapons.

It remains to be seen what new ideas the Trump administration will bring.

“What foreign policy can be implemented to make North Korea give up?” asked Tsuneo Watanabe, foreign and security policy expert with the Tokyo Foundation, a Japanese think tank. “So far, we haven’t seen an American president step up with a meaningful plan.”

The Obama’s administration’s policy of “strategic patience” with North Korea neither stopped that nation’s provocative acts nor ensured the safety of its neighbors. Japanese and South Korean officials derided the policy as an excuse for doing nothing.

That same tactic should not be replicated by Tillerson and the Trump administration, said Narushige Michishita, a foreign policy professor at the National Graduate Institute for Policy Studies in Tokyo.

“We cannot wait forever,” he said. “The situation is deteriorating, and the stakes are much too high.”

Already, six sets of U.N. sanctions have been slapped on Pyongyang since its first nuclear test in 2006. While the measures have cut North Korea off from much of the world economy, they have failed to halt the country’s military advances.

North Korea launched an unprecedented 21 ballistic missiles in 2016 and two nuclear detonations. It has launched five missiles in the first 69 days of this year.

New commercial satellite imagery of the snow-covered Punggye-ri nuclear test site indicates that North Korea is preparing for a sixth nuclear test, according to 38north.org, a website affiliated with the Johns Hopkins University that tracks North Korea.

The new activity comes after last Monday’s simultaneous launch of four ballistic missiles from the northwest corner of the country. The missiles traveled 620 miles eastward before splashing in the sea between Japan and the Korean peninsula.

North Korea said it launched the missiles as a response to the annual U.S.-South Korea military exercise, which Pyongyang sees as preparation for war.

U.S. Ambassador to the United Nations Nikki Haley told the U.N. Security Council recently that “all options are on the table” for the Trump administration’s dealings with North Korea. Thus far, however, the administration has not articulated a strategy.

“All of the efforts that we have taken thus far to attempt to persuade North Korea to, again, engage in meaningful negotiations have fallen short, to be honest,” State Department spokesman Mark Toner said in Washington last week. “So we need to look at new ways to convince them, to persuade them that it’s in their interest” to abandon nuclear ambitions.

william.hennigan@latimes.com