SEOUL, South Korea (AP) — Unpredictable. Unhinged. Dangerous.

Many South Koreans are using those words to describe the president of their most important ally, rather than the leader of their archrival to the North. They worry that President Donald Trump’s tough, unorthodox talk about North Korea’s nuclear program is boosting already-high animosity between the rival Koreas.

No matter whether Trump succeeds at getting North Korea to abandon its nuclear weapons and missile programs, his actions, comments and tweets are changing how the region views the long-running conflict. Senior North Korean officials see their relations with Washington as even more volatile than before. China is appealing for calm, and possibly re-examining its role. Japan is weighing a retaliatory strike capability against the North.

___

CHINA

After decades of failure to stop North Korea’s march toward a nuclear arsenal, some see Trump’s bluster as a shrewd attempt to press China, the North’s most important ally and trading partner, into pressuring North Korea more aggressively over its nuclear program.

Trump has said he’s willing to make trade and economic concessions to China in return for its help with North Korea. “A trade deal with the U.S. will be far better for them if they solve the North Korean problem!” Trump said on Twitter, recounting what he told Xi while hosting him this month at his Palm Beach, Florida, resort.

Pulling back from a campaign promise, Trump has also said he would not declare China a currency manipulator, as he looked for help from Beijing.

The rhetoric seems to be blurring the lines between North Korea and economic ties with China, issues that previous U.S. administrations had kept separate.

If such persuasion falls short, Trump has suggested he might use more coercive methods. So-called secondary sanctions on Chinese banks that do business with North Korea could also be in the offing, officials have said.

“Trump is posing a hard choice to Beijing — do something, something about North Korea and hope it generates some effects, or face American economic retaliation,” said Dean Cheng, senior research fellow at the Heritage Foundation in Washington, D.C. “Whether that works or not, it’s a very different strategy from the last three presidents.”

Koh Yu-hwan, a North Korea expert at Seoul’s Dongguk University, said that the way U.S. officials describe “maximum pressure and engagement” suggests that the Trump administration wants to ease Chinese fears about a collapse in North Korea, something that prevented Beijing from aggressively pressuring the North in the past.

“If the United States and China can set the tone, there will also be more opportunities for dialogue. It seems Trump could be more willing to cut a deal with North Korea than Obama was,” Koh said.

___

SOUTH KOREA

South Koreans may be uneasy about North Korea’s expanding arsenal of weapons, but many doubt that the country’s leader, Kim Jong Un, wants to start a war that would likely end in the destruction of his government and the ruling elite. Donald Trump is another story, judging by widespread concern posted on Twitter.

Some see him as a hot-tempered, unpredictable leader who might attack North Korea before it masters the technology to build a nuclear-tipped missile that could hit the U.S. mainland. North Korea is moving steadily toward that goal, and some experts believe it could achieve it during Trump’s presidency.

U.S. strikes earlier this month against Syria, coupled with Trump’s dispatching of what he called an “armada” of U.S. warships to the Korean region, touched off fears that the United States was preparing for military action, though it was revealed this week that the flotilla was taking a roundabout path to Korean waters and has yet to arrive.

Lim Eul Chul, a North Korea expert at South Korea’s Kyungnam University, doesn’t think Trump wants to attack North Korea but said he appears eager to send a message that war is possible.

That has driven North Korea to issue its own threats and begin preparations for “even a 1 percent chance that the U.S. will launch pre-emptive strikes,” Lim said. “That’s just how the authoritarian Kim government survives.”

The Kyunghyang Shinmun newspaper said recently that Trump is playing a “dangerous card” with his verbal threats, risking a miscalculation by Pyongyang and a war on the peninsula.

“Trump seems capable of doing anything, and he might choose to strike the North before it’s technologically able to strike back,” said Ray Kim, a 39-year-old Seoul resident. “Even if a war breaks out, it’s not like that war will take place on U.S. soil. Trump has much less to lose.”

___

NORTH KOREA

Trump is clearly on the mind of the North Korean leadership.

A senior Foreign Ministry official told The Associated Press last week that Pyongyang has been watching Trump’s actions — including his recent order for the strike on a Syrian air base and his many tweets about North Korea — and determined that his administration is “more vicious and more aggressive” than that of his predecessor, Barack Obama.

In response, Pyongyang is promising it will continue to build up its “nuclear deterrent” and respond in kind to any hostile moves, perceived or real.

North Korean fury at Washington was rising well before Trump took office, in particular over reports that annual U.S.-South Korean military exercises now include training for precision strikes on the North’s leadership or nuclear and military facilities. Pyongyang’s regime has called that “a red line,” and has since begun its own training for pre-emptive strikes and speeded up its testing of nuclear weapons and long-range missiles.

___

JAPAN

Japan is drawing up emergency responses in case of a North Korea missile strike. A number of municipalities are testing community alarm systems and planning evacuation drills as concerns run high around U.S. military bases. Both Japan and South Korea are home to tens of thousands of U.S. troops.

The rising tension has opened the door to debate about once-taboo subjects in Japan, where the disastrous World War II experience and a postwar constitution that renounced the right to use military force have created a strong pacifist streak.

Japan’s ruling party recently urged the government to introduce advanced missile-defense equipment such as a land-based Aegis or Terminal High Altitude Area Defense (THAAD) system, which is being introduced in South Korea.

Ruling party defense experts have even proposed that Japan lift a self-imposed restraint on conducting a retaliatory strike if attacked, rather than relying solely on the U.S. military.

The steady turning up of the heat on all sides has increased the possibility of a miscalculation that could result in an incident that escalates too quickly to be contained, or even outright conflict.

___

Associated Press Writers Eric Talmadge in Pyongyang, North Korea; Christopher Bodeen in Beijing; Mari Yamaguchi in Tokyo and Hyung-jin Kim in Seoul, South Korea, contributed to this story.

Copyright 2017 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.