SEOUL (Reuters) - South Korea’s Jeju Air said on Tuesday China has approved a plan to double its flights to the Chinese city of Weihai from June 2, boosting hopes of easing political tension between the two countries.

Relations between China and South Korea have been strained for months by a South Korean decision to deploy a U.S. anti-missile system, but have taken on a more conciliatory tone with the election this month of President Moon Jae-in.

Jeju Air, South Korea’s top low-cost carrier, said it first applied to increase its flights to Weihai, to 14 a week from 7, in early April, but China had not approved the plan because of the diplomatic row.

“The political tension has had a far-reaching impact on flights between the two countries including new flights, added flights and charter flights,” said a Jeju Air spokesman, Park Jung-Jun.

“The latest move raises hopes that the tension is easing,” he said.

However, he said China has not approved a request from his airline to resume charter flights between the two countries.

South Korean firms from airlines to automakers and retailers has suffered from China’s backlash to the decision last year to deploy the U.S. Terminal High Altitude Area Defense (THAAD) anti-missile system.

China says the system’s powerful radar can penetrate deep into its territory and undermine its security. South Korea and the United States have said the deployment is aimed purely at defense against North Korea.

Moon has pledged to seek a parliamentary review of the THAAD system, and sent his representative, Lee Hae-chan, to China to meet President Xi Jinping this month.

Xi told Lee that China wanted to put ties with South Korea back on a “normal track”, but he also urged it to respect China’s concerns and resolve tension over the THAAD deployment.

China’s tourism ministry has also instructed tour operators to stop selling trips to South Korea from March 15. An official at South Korean tour agency Mode Tour told Reuters it hoped the ban may be lifted as early as the second week of June.

Lotte Group has closed 74 of 99 retail stores in China after the group in late February approved a land swap outside Seoul to allowed South Korea to install the THAAD system. A Lotte Group official said on Tuesday that no stores had reopened yet.