China has lodged a diplomatic protest with the United States after Washington sanctioned two Chinese shipping companies for doing business with the Democratic People’s Republic of Korea (DPRK), the foreign ministry said Friday.

Beijing said it has consistently enforced all UN resolutions on the DPRK after the U.S. Treasury Department added two Chinese firms to a sanctions list on Thursday.

“We firmly oppose any country imposing unilateral sanctions and taking long-arm jurisdiction against any Chinese entity according to their own domestic laws,” said foreign ministry spokesman Geng Shuang.

Any Chinese company or individual found to be violating sanctions will be “dealt with according to laws and regulations,” Geng said.

“China has already made solemn representations to the U.S. on this matter and urged the U.S. to immediately stop its mistaken actions to prevent affecting bilateral cooperation on related issues,” Geng told reporters.