China has slammed a decision by the U.S. Treasury to sanction a Beijing-based cybersecurity company for its alleged role in multiple hacking incidents targeting critical U.S. infrastructure, while the Chinese cyber security agency complained Monday of attacks on Chinese networks.

Foreign Ministry spokesman Guo Jiakun slammed the accusations, saying at a daily news conference that China always firmly opposes and has cracked down on cyberattacks in accordance with law. It urges the US to stop using the issue to defame and smear China, he said.

China has strongly criticized the U.S. sanctions on a Beijing-based cybersecurity firm accused of hacking US infrastructure.

The U.S. on Friday sanctionedChina's Integrity Technology Group, accusing it of being behind a prolific hacking group known as "Flax Typhoon."

China slammed the U.S. Monday for sanctioning a Beijing-based cybersecurity firm allegedly behind a botnet targeting American infrastructure, accusing Washington of “using the issue of cybersecurity to vilify and smear China.