Chinese nationalists erupted in anger at South Korean boy band BTS after its leader thanked Korean War veterans for their sacrifices.
The singer, who goes by RM, made the remark in a recorded acceptance speech for an award from the Korea Society for promoting US-Korean relations.
"We will always remember the history of pain that our two nations shared together and the sacrifices of countless men and women," RM said in the speech, which included no mention of China.
"After 70 years, the world we are living in is much closer than before. Boundaries in many aspects are getting more blurred," RM said.
"As members of the global community, we should build a deeper understanding and solidarity to be happier together."
Chinese internet users and state media took RM's comments as a slap at China, whose soldiers fought alongside North Korean forces during their failed attempt to annex South Korea in the 1950-53 war.
They accused RM of ignoring the role played by China in the war, which Chinese Communist Party propaganda blames on the United States, instead of North Korean leader Kim Il Sung's attack on South Korea.
"Before, I thought some BTS songs were pretty good. Now, they seem to be covered in excrement," said a commenter on the microblog service Sina Weibo. "Insulting China is absolutely not allowed."
Online Chinese fan groups demanded an apology from BTS and called for boycotts of an upcoming album and promotional events.
BTS-related products were missing this week from the online stores of Samsung Electronics and sports brand FILA on Chinese e-commerce websites including Alibaba Group's TMall and JD.com.
BTS has yet to respond, but South Korean fans reacted angrily.
"BTS fans are from all over the world, so China's bullying will be known to all countries that took part in the Korean War," said Johnny Kim, a South Korean engineer.
The row comes ahead of Thursday's stock market debut of BTS's management company, Big Hit Entertainment.
Hong Kong's most prominent dissident, Joshua Wong, weighed in, criticizing Beijing for "provoking groundless rage and division."
"There are still many Korean War veterans around the world, including those from the United States, so it's not reasonable for China to pick a fight over this," said Min-seong Lee, a student in Seoul.