The New York Times reported quoting Microsoft that the code was installed by a Chinese government hacking group.

This report raises alarms because Guam, with its Pacific ports and vast American air base, would be a centrepiece of any American military response to an invasion or blockade of Taiwan, according to reports.

As per The New York Times, the code was installed with great stealth, sometimes flowing through routers and other common internet-connected consumer devices to make the intrusion harder to track.

The National Security Agency and Microsoft were set on Wednesday to publish details of the code that would make it possible for corporate users, manufacturers and others to detect and remove it.

According to The New York Times, the code is called a “web shell,” in this case a malicious script that enables remote access to a server. Home routers are particularly vulnerable, especially older models that have not had updated software and protections.

Microsoft called the hacking group “Volt Typhoon” which was part of a state-sponsored Chinese effort aimed at not only critical infrastructure such as communications, electric and gas utilities, but also maritime operations and transportation, reports The New York Times.

Microsoft says there is no evidence that the Chinese group has used the access for any offensive attacks.

Unlike Russian groups, the Chinese intelligence and military hackers usually prioritize espionage, according to reports.

Administration officials, in interviews, said they believed the code was part of a vast Chinese intelligence collection effort that spans cyberspace, outer space and, as Americans discovered with the balloon incident, the lower atmosphere, according to The New York Times.