BEIJING (Reuters) - China values trade with South Korea and is abiding by World Trade Organization (WTO) rules, the Commerce Ministry said on Thursday, after Seoul complained to the WTO about retaliation against South Korean firms over the planned deployment of a U.S. anti-missile system.


South Korea and the United States say the sole purpose of the Terminal High Altitude Area Defense (THAAD) system is to guard against missile launches from North Korea, but China says that its powerful radar could penetrate into its territory.


China is South Korea's largest trading partner and the dispute over THAAD has resulted in a sharp decline in Chinese tourists in the South's shopping districts.


Chinese authorities have also closed nearly two dozen retail stores of South Korea's Lotte Group amid the diplomatic standoff.


Chinese Commerce Ministry spokesman Sun Jiwen said that on March 17 at the WTO a South Korean representative had talked about South Korean companies in China being impacted.

"The Chinese representative said that China pays great attention to developing economic and trade relations between China and South Korea," Sun told a regular news briefing.

China has noted comments from a South Korean minister that there is no evidence to show China is taking "policy measures", Sun added.

"I want to add that, as a responsible member of the WTO, China has consistently and will continue to respect WTO rules and relevant promises," he added, without elaborating.

South Korea's trade minister said on Monday that the country had complained to the WTO.

Beijing has never explicitly linked the restrictions to the THAAD deployment.

The South Korean government has offered cheap loans and extended deadlines on existing debt to help businesses that have been affected and has pushed to diversify trade markets.

(Reporting by Yawen Chen and Ben Blanchard; Editing by Simon Cameron-Moore)