Beijing demanded on Wednesday that Seoul reverse course on the planned deployment of an advanced US anti-missile system to "avoid more serious negative impacts".

The remark came after reports of access restrictions in China to television series from the Republic of Korea and amid simmering anger among Chinese citizens.

On Tuesday, the ROK Defense Ministry signed a land swap deal with Lotte Group for the Terminal High Altitude Area Defense system in the name of handling "threats" from Pyongyang. However, experts said that while the system is of no use in that sense, its radar can cover parts of China and Russia.

"China has long held an active and open attitude on communication and cooperation with the Republic of Korea, but that needs the basis and atmosphere of public opinion," Foreign Ministry spokesman Geng Shuang said at a press briefing.

It was reported that Chinese websites had stopped screening new entertainment series from the ROK, while some Chinese TV stations no longer were inviting ROK performers to appear.

According to the ROK embassy in Beijing, China is the ROK's top trading partner, with trade volume reaching $171.8 billion in the first 11 months of 2016. Entertainment is one of the ROK industries that has most benefited from trade with China.

"We hope the ROK will cherish the precious achievements in the development of China-ROK ties, consider China's reasonable concerns and listen to calls from the public," Geng said.

He demanded that Seoul halt installation of the THAAD system to "avoid more serious impacts on bilateral relations, trade cooperation and civilian and cultural communication".

Geng said that China and Russia have vowed to "beef up coordination to handle the THAAD issue". The agreement came in a meeting between Assistant Foreign Minister Kong Xuanyou and Deputy Foreign Minister Igor Morgulov of Russia on Tuesday.

Su Xiaohui, a researcher of international strategies with the China Institute of International Studies, said Seoul has "opened Pandora's box" with THAAD.

The decision will place the security situation in Northeast Asia in a dilemma.

"There will be endless trouble," she said.

Su said ROK exports have benefited from opportunities opened by the China-ROK free trade agreement, which took effect at the end of 2015, but now THAAD implementation has hurt mutual trust, as well as friendly relations between the two nations.

lixiaokun@chinadaily.com.cn