South Korea’s political parties are ramping up criticism over China’s unauthorized construction of large steel structures in a disputed area of the West Sea (Yellow Sea), known as the Provisional Measures Zone (PMZ). Both the ruling People Power Party (PPP) and the opposition Democratic Party of Korea (DPK)—which has traditionally taken a more conciliatory stance toward Beijing—have voiced concerns, calling for an on-site investigation. Lawmakers warn that China may be employing a strategy similar to its actions in the South China Sea, where artificial structures have been used to assert territorial claims.
The PMZ is a maritime area where South Korea and China have agreed to temporarily suspend unilateral jurisdictional claims until a formal boundary is established.
DPK spokesperson Park Kyung-mee said on March 25, “We deeply regret the Chinese government’s construction of structures in the Yellow Sea and urge an immediate halt to the project, which could undermine the trust built between our two countries over the past 33 years of diplomatic relations.” The statement came a week after reports emerged that a South Korean maritime survey vessel had been threatened by Chinese forces near the structures in February.
Park added, “We had expected responsible action from the Chinese government, but it appears they have no intention of meeting such expectations.” She urged Beijing to cooperate in an investigation.
DPK Supreme Council member Kim Byeong-ju also issued a statement, calling the installations a “threat to maritime sovereignty” and suggesting they were an attempt by China to reinforce its claims along the 124-degree east longitude meridian. China has long asserted jurisdiction over waters west of this line, which would encompass roughly 70% of the Yellow Sea. Kim vowed the DPK would not remain passive and pledged to push for a parliamentary investigation, including an on-site inspection.
The DPK had previously remained largely silent on China’s actions in the Yellow Sea despite growing media attention. On March 24, Wi Sung-lac, a DPK lawmaker and former South Korean ambassador to Russia, was the first within the party to raise concerns in a parliamentary session, warning that China’s expanding influence in the region posed a serious security issue. “China’s efforts to expand its presence in the West Sea are a grave security concern,” he said. “Successive South Korean administrations should have taken this issue more seriously.”
His remarks prompted the party to take an official stance against Beijing’s actions. A DPK official later commented, “This is a serious provocation and a concerning development. We hope this issue will not be used for partisan attacks.”
The PPP has taken a stronger stance. Emergency steering committee chief Kwon Young-se, a former ambassador to China, said at a parliamentary forum on March 25, “This is not a simple civilian structure but a semi-fixed platform capable of oil drilling and surveillance activities. It appears to be part of China’s broader maritime strategy to expand its influence in the Yellow Sea.” PPP lawmaker Na Kyung-won proposed passing a parliamentary resolution to protect South Korea’s maritime sovereignty, while members of the National Defense Committee called on the government to take all necessary countermeasures.
The disputed structures are located within the PMZ under the 2001 South Korea-China fisheries agreement. Reports indicate they consist of two steel frames, each 70 meters in diameter and 71 meters high, along with facilities capable of housing personnel. China has claimed the structures are part of a private salmon farming operation in Shandong province. On March 24, Chinese Ambassador to South Korea Dai Bing reiterated this position in a meeting with Nam Sung-wook, a professor at Korea University, and others.
Despite Beijing’s claims, some South Korean officials and analysts suggest the installations could serve military purposes, potentially monitoring South Korean and U.S. military activity in the region. Experts warn that the submerged sections of the structures, which extend dozens of meters underwater, could house radar equipment capable of detecting submarine and naval movements. The area is a key route for China’s North Sea Fleet, and Beijing has increased its naval exercises and maritime survey activities in the Yellow Sea in recent years.
South Korean authorities first detected the structures in March 2020 during the Moon Jae-in administration. By March 2022, officials confirmed that Chinese personnel were stationed at the site and convened a National Security Council (NSC) meeting to discuss a response. However, the issue remained unresolved amid the country’s presidential transition. In December 2022, the Yoon Suk-yeol administration held another NSC meeting to review countermeasures, including a proposal to construct similar structures within the PMZ. The plan was ultimately shelved due to cost and technical challenges.
Legal experts argue that China’s construction of multiple artificial facilities in the PMZ could violate the South Korea-China fisheries agreement by restricting fishing and navigation. Kim Doo-young, former deputy registrar of the International Tribunal for the Law of the Sea, warned that under the United Nations Convention on the Law of the Sea, China could establish a 500-meter safety zone around each structure. “If China continues building these structures, the combined safety zones could cover tens of square kilometers, effectively barring South Korean vessels from entering,” he said.
