The couple, German nationals partially named as Xuejun C. and Hua S., were arrested in the southern city of Munich, said the federal prosecution service, which alleged that the pair "work for a Chinese intelligence agency".

Their homes and workplaces in Munich were being searched.

The couple are alleged to have "established contacts with numerous academics at German universities and research institutions, in particular with chairs in the fields of aerospace engineering, computer science and artificial intelligence".

To make these contacts, the couple are believed to have "posed as interpreters or as employees of an automobile manufacturer".

Some scientists were then "enticed to travel to China under the pretext of giving paid lectures to a civilian audience", but actually ended up addressing employees of state-owned arms manufacturers, prosecutors said.

As well as the suspects' arrests, prosecutors said that "further measures" were being carried out "concerning a total of 10 people who are not suspected of any offence but are potential witnesses" in Berlin, Munich and several other locations across the country.