North Korea Fires More Missiles as Seoul Puts Off U.S. Defense System

In comments to reporters on Wednesday, a senior official from the presidential Blue House in Seoul said that two launchers already installed could remain, but that four launchers yet to be deployed would not be set up until the administration completed an environmental assessment.

The missile defense system has been contentious in South Korea and has drawn sharp criticism from China, which views the system’s radar as a threat. Beijing has taken retaliatory economic measures against Seoul, including curtailing the flow of Chinese tourists and punishing South Korean companies in China.

During his campaign, Mr. Moon, who won the presidency last month, complained that the United States and the previous South Korean administration had rushed to deploy Thaad in order to present him with a fait accompli. His decision to suspend the installation could strain relations with the White House, which has taken a hard line in confronting North Korea and its nuclear weapons program. It could also hurt American efforts to present a tough, unified position with Japan and South Korea against the North.

Mr. Moon, who has said he wants to resolve the nuclear crisis through dialogue, has also suggested that South Korea must “learn to say no” to Washington. He has already signaled a softening stance toward North Korea by encouraging aid groups to visit the country, although the North has rejected those offers since Seoul supported new United Nations sanctions.

Analysts said that as people protested the Thaad installation and South Korean businesses pressured the government to improve relations with China, Mr. Moon might have decided that suspending the progress of the system was politically expedient.

“I think he is trying to find a diplomatic way to slow down the process to placate the business community and placate his political supporters,” said Stephen R. Nagy, senior associate professor of politics and international studies at International Christian University in Tokyo.

Mr. Moon may also have sensed that China was not going to back down. When Lee Hae-chan, South Korea’s special presidential envoy, visited Beijing last month, President Xi Jinping did not concede anything. China’s strategy is to stand firm against Thaad to force Mr. Moon to modify or even eliminate the system, which the Chinese suspect he does not like, either.

The defense system officially went into operation in late April on an abandoned golf course in Seongju, 135 miles southeast of Seoul, when two of six launchers were installed. United States military officials say it is “operational and has the ability to intercept North Korean missiles.”

In South Korea, any military installation on a site larger than 330,000 square meters requires a full analysis of the potential environmental and social effects. The ministry divided the site, which is 700,000 square meters, into two parcels to expedite the installation.

Supporters of Mr. Moon said he was simply working to ensure that the Thaad battery complied with the law.

“The previous administration wasn’t really clear and transparent about the review process, and basically, this is a legal procedure,” said Choi Jong-kun, a professor of political science at Yonsei University in Seoul.

Mr. Choi said the president was eager to follow the legal procedure given that his predecessor, Park Geun-hye, was impeached and ousted after accusations of corruption.

A spokeswoman for the American forces in South Korea referred requests for comment to the Blue House.

American military officials noted that the system became operational in April and therefore could provide basic, limited defense in the event of a North Korean attack, even if the additional launchers were not deployed.

“We continue to work with the Korean government on this and have been transparent about our actions through this process,” said Capt. Jeff Davis, a Pentagon spokesman.

Pentagon officials noted that the missile defense deployment was a result of an agreement reached last year. But they also acknowledged that, since President Trump has pulled out of international agreements reached by his predecessor, Barack Obama, there is precedent for Mr. Moon’s move.

Opponents of Mr. Moon said the suspension was probably a first step toward rejecting the defense system altogether. Oh Shin-hwan, a spokesman for the conservative-leaning Bareun Party, said in a statement that because the environmental review would take more than a year to complete, “the government does not intend to deploy the remaining four launchers.”

“North Korean provocations are occurring almost every day,” the statement said. “And South Korea is saying that it will defend the country with half of the Thaad system.”

Analysts said it was too early to predict the outcome of the assessment. The early deployment “was rushed, so if the rush has been slowed down a bit, it’s not the end of the world,” said Gordon Flake, the chief executive of the Perth-U.S. Asia Center at the University of Western Australia.

But, he added, Mr. Moon “has to be aware of a fundamentally changed strategic environment in the last several years in Northeast Asia.” As North Korea rapidly develops the capability to strike Japan and American bases in the region, Mr. Flake said, “decisions that South Korea makes have regional and global implications.”

Scott A. Snyder, senior fellow for Korea studies and director of the program on United States-Korea policy at the Council on Foreign Relations, said in an email that American officials should explain the need for the defense system to the new administration, and that Mr. Moon’s supporters should not reject it simply because Ms. Park had approved it or give in to pressure from China.

“Thaad is at risk of becoming overly politicized,” Mr. Snyder wrote. “And both sides need to take a deep breath and reaffirm common objectives and means for dealing with them rather than allowing Thaad to become a neuralgic and reflexive object of confrontation.”