BEIJING (AP) — China says it will look into charges against two Chinese firms sanctioned by the U.S. for suspected violations of sanctions against North Korea.

Foreign Ministry spokesman Geng Shuang said Friday that China upholds all United Nations Security Council sanctions against the North over its nuclear and missile programs.

However, he said Beijing opposes unilateral sanctions on Chinese firms such as those imposed by the U.S. separate from those of the U.N.

The Trump administration on Thursday sanctioned Dalian Haibo International Freight Co. Ltd. and Liaoning Danxing International Forwarding Co. Ltd. for using deceptive methods to circumvent international and U.S. sanctions and the U.S. commitment to implementing U.N. Security Council resolutions.

Calls to the two companies rang without response Friday or were answered by people who immediately hung up the phone.