The US Treasury Department notified Congress in a letter on Monday that a Chinese state-sponsored actor hacked its systems through a third-party software provider.

The software provider, BeyondTrust Inc. notified the Treasury Department of the breach on Dec. 8, saying a hacker “gained access to a key used to secure a cloud-based service by vendor Offices (DO) end users, Bloomberg The letter described the breach as a “major cyber security incident,” the report said.

After being notified of the breach, the Treasury Department immediately notified the Cybersecurity and Infrastructure Security Agency and “as it worked with law enforcement partners across the government to review the incident,” it said. The Wall Street Journal said.

Treasury’s roles include monitoring financial data, imposing sanctions.

According to The New York TimesThe Treasury Department is of interest to top Chinese officials because the agency’s role includes monitoring “sensitive” global financial system data, including projections of China’s economy. “The department also imposes sanctions against Chinese firms, including, most recently, those aiding Russia in its war against Ukraine,” Times said.

The finance department did not immediately return the call. Anastopedia Request for comment.

Liu Pengyu, a spokesman for the Chinese embassy in Washington, DC, denied the reports, saying that “China strongly opposes the US attacks against China without any facts.”

“China itself is a target of international cyber-attacks, and constantly opposes and counters all kinds of cyber-attacks,” Liu said in an email response.

Update—December 31, 2024: This article has been updated to include a response from a Chinese embassy spokesperson.