China has slammed a decision by the US Treasury to sanction a Beijing-based cybersecurity company for its alleged role in multiple hacking incidents targeting critical US infrastructure, while the Chinese cyber security 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 cyber attacks and that Washington was using the issue to “defame and smear China.”

“For some time now, the US side has been playing up so-called Chinese cyber attacks 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.

“They pose a major threat to China’s domestic networked units and internet users and some activities have been suspected of criminal offenses,” the center said in a notice on its WeChat social media site.

On Friday, the Treasury’s Office of Foreign Assets Control hit Integrity Technology with sanctions that block access to US property and bank accounts and prevent the targeted people and companies from doing business with Americans. It cited alleged multiple hacks against US victims, including incidents attributed to Flax Typhoon, a Chinese state-sponsored campaign that targets US critical infrastructure.

The sanctions did not appear to be related to an incident in which the Treasury Department reported that Chinese hackers had remotely accessed several of its workstations and unclassified documents in a major breach of cybersecurity.

The Treasury Department said it learned of that problem on Dec. 8, when a third-party software service provider, BeyondTrust, flagged that hackers had stolen a key “used by the vendor to secure a cloud-based service used to remotely provide technical support” to workers.

US officials are grappling with the fallout from a massive Chinese cyberespionage blitz known as Salt Typhoon that they say gave officials in Beijing access to private texts and phone conversations of an unknown number of Americans.

Late last month, officials said at least eight telecommunications companies, as well as dozens of nations, had been affected by Salt Typhoon.

Integrity Technology said the sanctions would not adversely affect its business since it does not operate in the US and has no assets there. It added that it abides by all laws and regulations and that it “has always adhered to the corporate vision and mission of bringing a sense of security to the world.”