China has rejected the South China Sea verdict.
Chinese police and state-run media on Wednesday called for "rational patriotism" after sporadic protests broke out against the US across China following an international tribunal's verdict rejecting Beijing's claims over strategic South China Sea.
The police warning came after video clips posted online showed protesters, who believe the US was behind the ruling, demonstrating outside restaurants owned by the US fast-food chain KFC in cities such as Hebei, Jiangsu, Shandong and Hunan, state-run China Daily reported.
Several demonstrators held red banners saying "Join the boycott against US, Japanese and Philippine companies, and be a patriotic Chinese" and stopped people from entering the restaurants.
Police officers were dispatched to the protests site to maintain public order. Protests in China are rare.
In recent years the ruling Communist Party of China has encouraged people to stage protests against Japan over the dispute over the islands in East China Sea.
Police have strengthened security at the Philippines embassy in Beijing after the tribunal on July 12 upheld the Philippines rights over the South China Sea.
China has rejected the verdict and said it will not have any impact on its stand that over 90 per cent of the South China Sea belonged to it.
A KFC employee surnamed Lei in Chenzhou, Hunan province, confirmed there had been a small protest outside the restaurant on Monday. She said that business returned to normal on Wednesday, China Daily reported.
In a widely circulated video, a woman in Tangshan walked into the restaurant and told customers that it is they who pay for the bullets for the US.
Yum! Brands Inc, China Division, which operates the KFC chain in the country, declined to comment on the protests. The protests have been criticised by the police and public.
After one such protest was held at a local KFC, police in Ganyu district, Lianyungang, Jiangsu province, issued a statement yesterday urging people to not get involved in illegal protests instigated via the internet or social media.
In Siyang county, Jiangsu, police posted on their micro blog the message, "Love your country, but please don't take out your anger on its people."
Pu Yu, 27, a Tangshan resident who works in Beijing, said she did not understand such behaviour.
"They are simply creating chaos in the name of patriotism. If KFC closes down, it's the locals who will be out of jobs," she said.