Sergeant Korbein Schultz, who held a top-secret security clearance, was taken into custody at Fort Campbell, a military base on the Kentucky-Tennessee border, the Justice Department said in a statement.

Schultz's indictment did not identify the country he was allegedly supplying with sensitive military information, but press reports identified it as China.

According to the indictment, Schultz, since June 2022, provided a contact in Hong Kong with documents, maps and photographs relating to US national defense.

Schultz was allegedly paid a total of $42,000 for the information.

The Justice Department said it included information about potential US plans in the event that Taiwan came under military attack.

It also included documents related to fighter aircraft and helicopters, hypersonic equipment, the High Mobility Artillery Rocket System (HIMARS) and studies about the US and Chinese military.

Asked on Friday about Schultz's arrest, as well as that of a Chinese software engineer held this week for allegedly stealing artificial intelligence technology from Google, Beijing said it was "not aware of the specific circumstances" of the cases.

But spokesperson Mao Ning said in reference to the Google case that "China has consistently attached high importance to and actively protected intellectual property rights".

"At the same time, we also oppose the United States abusing its national power to groundlessly suppress Chinese enterprises and Chinese citizens," she told a regular briefing.

Schultz's indictment also comes shortly after the arrests in California of two US Navy sailors on charges of spying for China.

Petty officer Wenheng Zhao was sentenced to 27 months in prison in January after pleading guilty to charges of conspiring with a foreign intelligence officer and accepting a bribe.

Zhao and another US sailor, Jinchao Wei, were arrested in August.