BANGKOK — 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 cybersecurity agency complained Monday of attacks on Chinese networks.

Asked about the sanctions against Beijing-based Integrity Technology Group, Chinese Foreign Ministry spokesperson Guo Jiakun said the country has cracked down on cyberattacks and that Washington was using the issue to “defame and smear China.”

“For some time now, the U.S. side has been playing up so-called Chinese cyberattacks and has even initiated illegal unilateral sanctions against China,” Guo said. “China firmly opposes this and will take necessary measures to safeguard its legitimate rights and interests.”

Integrity Technology Group said the move by Washington had “no factual basis.”

“The company firmly opposes the U.S. Treasury Department’s unwarranted accusations and Illegal unilateral sanctions on the company,” the company, also known as Yongxin Zhicheng Technology Group, said in a statement Monday to the Shanghai Stock Exchange.

The China National Cyber Security Information Center said it had discovered attacks from various malicious websites and foreign IP addresses, including some in California and Florida. It also reported attacks from the Netherlands, Singapore, Mexico, Turkey and Vietnam using Trojan programs, botnets, phishing, theft of intellectual property and violations of privacy.

On Friday, the Treasury’s Office of Foreign Assets Control hit Integrity Technology with sanctions that block access to U.S. property and bank accounts and prevent the targeted people and companies from doing business with Americans.

It cited alleged multiple hacks against U.S. victims, including incidents attributed to Flax Typhoon, a Chinese state-sponsored campaign that targets U.S. critical infrastructure.