BEIJING/SHANGHAI (Reuters) - Royal Caribbean Cruises Ltd RCL.N will remove visits to South Korean ports from its China cruises, the firm said in a statement, amid rising tension between the two countries over Seoul's deployment of a U.S. missile defense system.

The Royal Caribbean's cruise ship Explorer of the Seas arrives back at Bayonne, New Jersey January 29, 2014. REUTERS/Carlo Allegri

In a post on its Chinese website, the U.S. cruise operator, one of the world’s biggest, said it had changed its China-based cruises to remove visits to popular South Korean resorts because of “recent developments regarding the situation in South Korea”.

The move makes Royal Caribbean one of the first major travel firms to publicly stop or restrict trips to South Korea after media reports last week that Beijing had given guidance to tour operators in China to stop selling trips to the country.

A South Korean government document seen by Reuters said China gave a “7-point” verbal instruction to travel firms regarding a ban on trips to South Korea. One point blocked China-based cruise ships from docking in South Korean ports.

In a notice posted on Thursday, Royal Caribbean detailed changes to itineraries for cruises leaving from Chinese ports. These removed visits to South Korean destinations such as Busan, Jeju and Seoul, replacing them with visits to sites in Japan.

The firm did not respond to requests for further comment on Thursday. Rival cruise operators including Carnival Corp CCL.N did not immediately respond to requests for comment.

The squeeze on Korean firms underlines Beijing’s anger over a joint plan by South Korea and the United States to set up the Terminal High Altitude Area Defence (THAAD) missile system in South Korea. Seoul and Washington say it will defend against nuclear-armed North Korean missiles, but Beijing says its far-reaching radar is targeted at China.

The crackdown has sent a chill across South Korea’s retail and tourism sectors, which rely heavily on China trade. Chinese shoppers are big consumers of South Korean products from cosmetics and television dramas to vacations and music.

The number of Chinese tourists to South Korea has nearly quadrupled to 8 million over the past five years, accounting for nearly half of foreign visitors, Korean government data showed.

South Korea has said it will consider filing a complaint against China to the World Trade Organization over what it described as trade retaliation over the THAAD deployment issue.