Zhang Hongsen, head of China’s powerful media regulator, says that the country’s blockade against South Korean films and TV shows is an “emotional issue.”

Zhang, deputy director of the State Administration of Press Publication Radio Film and Television (SAPPRFT), was speaking on Friday in Beijing on the sidelines of the Communist Party’s once-in-five-years National Party Congress.

China has boycotted many South Korean goods and services since July 2016, when the Korean government agreed to allow the deployment of the American THAAD missile defense system. The South Korean government argues that the system is needed to protect itself from a nuclear-armed and belligerent North Korea. China says the system’s radar can be used for spying.

Zhang gave no indication of when the blockade would end and said that it depends on people’s feelings and emotions.

“Cultural exchanges are not ordinary trade in goods or commodities. They bear on the friendship of peoples and their sentiment towards each other. Friendship and their heart to heart communication,” he said. “Cultural exchanges will surely develop in a positive direction.”

Chinese officials have rarely acknowledged the boycott, though it has become increasingly obvious as Chinese TV and Internet firms ceased broadcasting Korean shows, and as Chinese film festivals have repeatedly failed to select any Korean movies. Zhang suggested that exchange was continuing and said that Chinese film makers at this week’s Busan festival were evidence.

The China box office has marched on, without Korean films. Zhang forecast that gross revenues this year would hit $8.31 billion (RMB55 billion). That is a 20% increase from last year’s totals of $6.58 billion and (RMB45.7 billion).

Korean entertainment companies, including those in post-production services which had invested in China have retreated or scaled down their China operations and have repatriated staff back to Korea. Others have found co-productions are no longer possible.

The boycott has extended far beyond TV shows, K-Pop and film. South Korean car makers, cosmetics and electronics firms have suffered similarly. Lotte, which also has cinema operations in China, recently agreed to sell off its Chinese supermarket chain.