A US Navy guided missile submarine.

US Navy | AP

The US Navy was affected by the Chinese state-sponsored hack revealed by the Microsoft earlyr this weekNavy Secretary Carlos Del Toro told CNBC’s Morgan Brennan on Thursday.

Del Toro said the U.S. Navy “has been affected” by the cyberattacks, adding that it was “no surprise that China has behaved in this way, not just for the last few years but for decades.”

He declined to provide further details about the breach but suggested the Navy had been dealing with cyberattacks like this for years.

Microsoft issued an alert along with top intelligence agencies and the Cybersecurity and Infrastructure Security Agency on Wednesday, warning businesses and public companies that a sophisticated Chinese state-backed hacker group had successfully exploited a vulnerability in a popular cybersecurity suite.

The vulnerability, which was exploited by a group codenamed “Volt Typhoon,” affects critical cyber infrastructure across a range of industries, Microsoft said Wednesday. Microsoft noted that the Chinese hackers had targeted communications and maritime sectors in Guam, which is home to a key US military base.

The hacking group appears to have been focused on surveillance rather than disruption, Microsoft noted. But top intelligence officials and scientists expressed concern that Guam had been targeted, said The New York Times that the island’s territory would be crucial to warding off a long-feared invasion of Taiwan by China.

The Chinese Foreign Ministry and state-controlled press have dismissed the findings by Microsoft and the intelligence agency as “disinformation.”

Earlier on Thursday, a State Department spokesperson said it was important for both the government and the public to remain vigilant. “We will continue to work with our allies and partners to address this critical issue,” spokesman Matthew Miller said at a briefing.