The suspect, partially named as Martin D., worked for a US Defense Department contractor between 2017 and 2023, prosecutors told the court in the western city of Koblenz.

This included working at a US military base in Germany from at least 2020.

In 2024, the suspect allegedly "contacted Chinese government agencies several times and offered to pass on sensitive information from the US military to a Chinese intelligence service," prosecutors said when the suspect was charged.

Martin D. was arrested in Frankfurt in November 2024 and charged in August.

Berlin has seen an increase in suspected spying cases linked to Russia since the Ukraine war, and to China, with ties to Beijing under growing pressure.

In October, a German-Russian national was sentenced to six years jail for spying for Moscow and plotting sabotage acts to undermine Germany's support for Ukraine.

In the most high-profile case to involve China, a former aide to German far-right lawmaker Maximilian Krah in the European parliament was jailed for four years and nine months in September on spying charges.

A court in Dresden found Jian Guo guilty of acting as an agent for a Chinese intelligence service while working for Krah, a member of the anti-immigration Alternative for Germany (AfD) party.