Germany has arrested a citizen of the United States suspected of offering intelligence on the US military to China while working for US forces in Germany, the Office of the Federal Prosecutor says.

According to German prosecutors, the man, identified only as Martin D under German privacy law, was arrested in Frankfurt on Thursday.

In a statement, prosecutors said he is accused of having declared himself ready to work as an agent for a foreign intelligence agency and he had “contacted Chinese officials in 2024 and offered to hand them sensitive information about the US military”.

They said the accused had worked for US forces “until recently”. The investigation is being carried out “in close co-ordination” with German intelligence, prosecutors added.

China and the US have not yet responded to news of the arrest.

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

Last month, Germany warned of an increased risk of espionage from Beijing and tightened security checks for staff in sensitive areas of government and business.

In April, three Germans were arrested on suspicion of working to hand over technology that could strengthen China’s navy. The same month, a European Union staffer of a far-right German politician was accused of working with Chinese intelligence.

Anxiety about alleged Chinese spying has mounted elsewhere across the West in recent months as well.

In March, the US and Britain accused Beijing of cyberespionage against millions of people, including lawmakers, academics and journalists, as well as companies such as defence contractors.

At that time, China’s Ministry of Foreign Affairs spokesperson Wang Wenbin said reports of Chinese espionage in Europe were “hyped” and “intended to discredit and suppress China”.