A view of the Lotte Department Store in Shenyang in northeastern China’s Liaoning province on March 3. Four stores of South Korea's Lotte Group were closed in China by authorities, according to news media reports on March 6. (Li Lin/European Pressphoto Agency)

China warned Tuesday of “consequences” for South Korea and the United States over the deployment of a U.S. antimissile system, further raising regional tension and posing a challenge to the Trump administration.

The stern words came a day after North Korea launched four missiles that landed off the Japanese coast — an exercise, the North Korean government said, designed to practice for an attack on U.S. military bases in Japan.

American and South Korean officials say the continuing missile launches by the North Koreans demonstrate why the new antimissile system is necessary as a defense against Kim Jong Un’s regime. The U.S. military began deploying the Terminal High Altitude Area Defense (THAAD) system to South Korea on Monday.

But Beijing sees the system as a threat to the Chinese military and evidence of U.S. “meddling” in East Asian affairs.

“I want to emphasize that we firmly oppose the deployment of THAAD,” Geng Shuang, a spokesman for China’s Foreign Ministry, said Tuesday at a daily news briefing in Beijing. “We will resolutely take necessary measures to defend our security interests.

(Youtube/Osan AirBase)

“All consequences entailed from this will be borne by the U.S. and the Republic of Korea.”

Geng did not provide details on what “consequences” are in store for either country, although South Korean officials said they expected retaliatory moves against companies doing business in China.

The stepped-up tensions in East Asia create a potentially difficult and multipronged problem for the United States, involving: South Korea, in the midst of internal political turmoil; North Korea, often unpredictable; Japan, a steadfast U.S. ally with a weak economy and an ambition to expand its military footprint; and China, far and away the most powerful country in the region, both a U.S. rival and a key trading partner.

At the same time, a diplomatic battle between North Korea and Malaysia after the assassination of Kim Jong Un’s half brother in Kuala Lumpur escalated sharply Tuesday as Pyongyang banned all Malaysians from leaving its territory, prompting the Malaysian government to accuse it of hostage taking.

Malaysia retaliated by banning all North Koreans from exiting its borders and warning the Kim regime that it was inviting further international opprobrium. China was angered by the Feb. 13 murder, which the Malaysians say employed VX nerve agent, and some analysts suggest the North Korean missile launch was secondarily designed to provoke Beijing.

In Washington, State Department spokesman Mark Toner reiterated U.S. criticism of North Korea and the missile ­launches. “They’re increasingly becoming a pariah through this kind of behavior,” he said. “We’re pursuing tougher and tougher sanctions, but we’re also looking at other means to make that message clear to them.”

China’s Foreign Ministry did not specify any actions against the United States on Tuesday, but Beijing’s displeasure over the antimissile system marked an abrupt change in tone after a generally cautious approach until now toward the new American president.

Although some Chinese initially welcomed the idea of Donald Trump’s presidency, convinced a seasoned businessman would take a practical approach to politics, Trump’s early moves on Taiwan spooked Beijing.

Since the inauguration, Chinese officials have taken a careful approach, playing up the positive and playing down areas of disagreement, including Trump administration comments on the South China Sea. That is, until Geng’s statement on Tuesday.

Plans to deploy the THAAD system, which predates the Trump presidency, have long been a source of tension between Seoul and Beijing.

In the run-up to the deployment, China has taken aim at South Korean businesses in China. Beginning on Friday, it has been warning would-be Chinese tourists against booking trips to South Korea.

Although some travel agencies have already stopped selling tickets and tours to South Korea, China’s National Tourism Administration has officially ordered travel agencies to stop all tour groups and cruise ships by March 15, the South Korean official said. 

The new measures would also shut down duty-free shops run by Lotte, the South Korean conglomerate that helped Seoul secure land for THAAD, according to the South Korean official.

A representative of China’s Tourism Administration said by phone that the agency has indeed advised travel agencies not to sell South Korea tours or tickets.

The South Korean official and the Chinese tourism representative spoke on the condition of anonymity because they were not authorized to give information to the news media.

Three large Chinese travel agencies confirmed the order from the Tourism Administration. Two said they have already stopped selling packages; the other said it would stop selling by March 15.

After Lotte helped the South Korean government secure land for THAAD, it was denounced and threatened in China’s Communist Party-controlled press. Nearly two dozen of the company’s retail outlets were subsequently shut down by Chinese authorities for alleged safety violations.

China recently rejected applications by Korean airlines to add charter flights on popular tourists routes, a move interpreted in South Korea as a warning on the missile system.

There have also been scattered efforts to implement a pop-culture blockade, with South Korean television programs pulled from Chinese websites, calls for boycotts of South Korean cosmetics and canceled K-Pop (Korean pop) shows.

Politically motivated attacks on foreign business are strikingly at odds with China’s recent calls to protect globalization and free trade, most notably President Xi Jinping’s keynote speech at the World Economic Forum in Davos, Switzerland.

On Monday, South Korea said it was considering filing a World Trade Organization case against China, according to the local news media.

Joo Hyung-hwan, South Korea’s trade minister, said Seoul would “seek international action against possible violations of the World Trade Organization and the Seoul-Beijing free trade agreement.”

He also pledged to help South Korean companies deal with any “discrimination” they face.

The South Korean official called China’s moves “regrettable,” noting that curbing business will hurt Chinese vendors, too.

North Korea’s missile launch on Monday further complicates the tensions. The state-run Korean Central News Agency said the four missiles were intended as practice for an attack on “the bases of the U.S. imperialist aggressor forces in Japan.” After a flight of about 600 miles, they all fell into the Sea of Japan; three of them came down inside Japan’s exclusive economic zone.

The United States has about 54,000 military personnel in Japan.

Anna Fifield in Tokyo, and Congcong Zhang and Jin Xin in Beijing contributed to this report.