Controversy is growing over a trip to Beijing taken by opposition lawmakers, as top Chinese officials have called for a halt to South Korea’s plan to station a US missile shield while shunning official diplomatic consultations.

An eight-member delegation led by Rep. Song Young-gil of the main opposition Democratic Party of Korea is currently visiting China. The group, which includes Park Sun-won, a former unification and security secretary to former President Roh Moo-hyun, said it would address Beijing’s ongoing economic retaliation against the plan to deploy the Terminal High Altitude Area Defense anti-missile system here.

But the trip has kindled backlash, as the party has adopted opposition to the THAAD program as part of its platform. The ruling Saenuri Party and other lawmakers, such as Rep. Yoo Seong-min of the to-be-launched New Conservative Party for Reform, likened the visit to “selling out the country.”

The outrage intensified after Chinese Foreign Minister Wang Yi told the delegation Thursday the deployment process should be “delayed and frozen” if South Korea wants to expand cooperation with Beijing. If Seoul accelerates the process, it will “provoke” China, which is “unwise and not good,” Wang said.

“Any issue subject to military and national sovereignty cannot be compromised in any case anywhere. Their act of humiliating diplomacy shows that it’s extremely dangerous to entrust national security to such people,” Yoo said at a party meeting Thursday.

“If you set this kind of diplomatic precedent, China would seek to damage our sovereignty again with financial pressure. China knows well about our internal situation and is trying to divide, alienate and shake us.”

Saenuri Party Floor Leader Rep. Chung Woo-taik also slammed the lawmakers for “bargaining” over the nation’s military sovereignty.

“The Democratic Party lawmakers simply asked to lift the retaliatory measures on trade without presenting their own position on the THAAD issue, which represents absurd, humiliating diplomacy beyond toadyism that they try to barter national security in return for money,” he said at a separate party meeting.

Seoul‘s Deputy Foreign Minister Kim Hyoung-zhin called in Chinese Ambassador Qiu Guohong earlier in the day apparently to raise issue with Wang’s remarks and also discuss illegal fishing by Chinese ships and this year’s 25th anniversary of bilateral ties.

“The envisioned deployment of the THAAD system is a sovereign, self-defensive measure to defend national security and people’s lives from North Korea’s nuclear and missile threats,” Foreign Ministry spokesman Cho June-hyuck said at a regular news briefing.

“We believe that any certain issue must not affect the development of a bilateral relationship and economic, cultural and people-to-people exchanges should be steadily improved and strengthened.”

After years of cordiality, relations between Seoul and Beijing have been icy since the THAAD deployment decision was announced last July. 

Signs of economic retaliation have also risen, along with complaints from South Korean businesses in China. Cultural exports have taken a direct hit, with rumors of an unofficial ban on Hallyu spreading.

Meanwhile, China has since virtually brushed off requests for related discussions from Seoul and its embassy in Beijing. Ambassador Kim Jang-soo last met with Wang during a visit by Prime Minister Hwang Kyo-ahn in June.

Foreign Minister Yun Byung-se has said the government is working to devise intra-agency steps to cope with Beijing’s perceived retaliation.

The progressive party also triggered criticism when six of its first-term legislators traveled to Beijing in August last year.

During their three-day stay, the delegation held a seminar with a state-run think tank and a dinner meeting with scholars. On Friday, it is scheduled to meet with Kim Jang-soo and Fu Ying, a former vice foreign minister who now chairs the foreign affairs committee of the National People’s Congress, before returning home.