The German federal prosecutor's office accused three of its citizens, identified only as Herwig F., Ina F. and Thomas R., on Thursday of obtaining "information on innovative technologies that could be used for military purposes".

Between February 2017 and April 2024, "they repeatedly collected information that could in particular be useful for expanding China's naval combat power", prosecutors said in a statement.

Beijing said on Friday it hoped "Germany will stop hyping up so-called espionage risks from China and not set up obstacles to the healthy and stable development of China-Germany relations".

"China has always adhered to developing China-Germany relations based on the principle of mutual respect, non-interference in each other's affairs and... abiding by laws and regulations," foreign ministry spokesman Guo Jiakun told a regular news conference.

The German prosecutors said Thomas R. had "acted as an agent for an employee of the Chinese intelligence service MSS based in China" from 2017.

He is said to have made contact with married couple Herwig F. and Ina F., who ran a company in the western city of Duesseldorf.

The group was arrested in April last year and officially charged in December.

China's relations with Germany have been strained by several recent high-profile cases of alleged spying.

A Chinese woman was arrested in Germany in October and accused of spying on defence industry installations.

The woman allegedly reported to another suspected Chinese spy, Jian G., who is now under arrest but worked in the office of a far-right German deputy in the European Parliament.

In December, China's foreign ministry accused Germany of "manipulation and smearing" after police launched a probe against a Chinese man who was reported to have taken photographs at naval bases on Germany's Baltic Sea coast.