SEOUL -- Citing the threat from North Korea, Washington and Seoul have announced plans to deploy the U.S. antiballistic missile system known as THAAD in South Korea -- a move that drew strong objections from China.
The decision to deploy the Terminal High-Altitude Area Defense system was formally announced at a news conference Friday in Seoul by Gen. Thomas Vandal, chief of staff for the U.S. forces in South Korea, and South Korea's deputy minister of defense, Ryu Je-seung.
"North Korea's continued development of ballistic missiles and weapons of mass destruction, in opposition to its commitments to the international community, require our alliance to ensure that we retain the ability defend ourselves in the face of this threat," Vandal said.
The system "will be focused solely on North Korean nuclear and missile threats and would not be directed towards any third party nations," the Pentagon added in a statement.
China, which shares a border with North Korea, has been voicing its opposition to THAAD for months.
"China is very unsatisfied and resolutely opposes" the move, China's Foreign Ministry said in a statement Friday. "The missile system is unhelpful in realizing the goal of denuclearization of the Korean Peninsula, is no good for the stabilization of the peninsula, runs counter to the effort of various parties' negotiations, and will severely damage the safety of China and nearby countries and the regional strategic balance."
The ministry urged Washington and Seoul to reconsider and to refrain from actions that "complicate the regional situation" and "harm China's strategic and security interests."
China's ambassador to South Korea has also warned that system could undo recent progress in relations between Beijing and Seoul and "create a vicious cycle of Cold War-style confrontations and an arms race."
John Delury, a professor at Yonsei University in Seoul, said Friday that the move "shifts the wind in bilateral relations between China and South Korea. China has made it clear that this is a kind of red-line issue for them. Going with THAAD is going to mean that South Korea will take a hit in its ability to seek cooperation from China regarding North Korea."
THAAD is designed to shoot down short, medium and intermediate ballistic missiles as they fall downward toward earth, not during the upward part of their trajectory.
China is apparently concerned not so much that deploying THAAD in South Korea would allow the U.S. to shoot down Chinese missiles but that the system's radar could give Washington better early warning and tracking of Chinese missiles. The U.S. already has deployed the system in Hawaii, Guam and elsewhere.
Adm. Harry Harris, commander of U.S. forces in the Pacific, has said that Beijing had the power to stop the deployment of THAAD in South Korea by pressuring Pyongyang to halt its missile activities.
"If China wanted to exert a lot of influence on somebody to prevent THAAD from being considered going into Korea," he told reporters in February, "then they should exert that influence on North Korea."
Washington and Seoul began intense consultations on THAAD immediately after Kim Jong-un's regime launched a long-range rocket in early February that Pyongyang claimed put a satellite into orbit. In April, North Korea said it successfully tested an engine designed for an intercontinental ballistic missile and in June launched what the U.S. said appeared to be two intermediate-range ballistic missiles.
The U.S., Japan and South Korea won backing from China at the United Nations for tighter sanctions on North Korea after Pyongyang's nuclear test and long-range rocket launch in February.
But Delury said South Korea's decision to embrace THAAD might cause China to be less strict with its unpredictable neighbor.
"South Korea is always asking that China enforce sanctions [on North Korea] harder. It's going to be difficult for them to ask that now, and China will likely be less receptive to those requests," he said.
"It also gives China an opening to try to improve ties with North Korea, which Xi Jinping wants to do even though Kim Jong Un drives him crazy. He's likely now to seek a way to use Chinese influence more effectively in North Korea."
The system will be operated by U.S. forces in South Korea.
Ryu, South Korea's deputy minister of defense, said a joint U.S.-South Korea team had "confirmed the military effectiveness of THAAD" and was working on final preparations to propose the best site for the battery.
Although some of North Korea's recent missile launches have been described as failures, each successive test helps Pyongyang further refine its technology, experts say.
Daniel Pinkston, a lecturer in international relations at Troy University in Seoul, called the decision to deploy THAAD inevitable and not surprising.
"With the pace of North Korea's missile development, and the fact that South Korea's own missile defense system is still a ways off in terms of being effective to address the threat posed by North Korea, deploying THAAD is a prudent move," he said. "The fact that North Korea keeps testing and developing their own missiles makes it politically easy to announce it now."
Pinkson called concerns that deploying THAAD may risk South Korea's relations with China "exaggerated."
"The system is designed to prevent a missile landing on a densely populated South Korean city," he said. "There's no reason for anyone to disapprove of THAAD unless they're planning a missile attack on a South Korean city."
South Korea's main opposition, the liberal Minjoo Party, issued a statement saying that while it didn't oppose the deployment of THAAD, it was "regrettable" that the decision was "rushed," without more deliberations in parliament and with the public.
But Kim Jong-dae, a defense analyst and lawmaker with the left-wing Justice Party, held a news conference Friday afternoon at the National Assembly in Seoul, where he announced his party's opposition to the deployment of THAAD, calling it "truly outrageous."
He argued that the deployment would only heighten tensions in East Asia by antagonizing China as well as Russia, which also has expressed opposition to THAAD in South Korea.