BERLIN (Reuters) - Three German nationals have been arrested on suspicion of working with the Chinese secret service to hand over technologies that could be used for military purposes, German prosecutors said on Monday.

The suspects were identified as Herwig F. and Ina F, a married couple who run a company in Dusseldorf, and Thomas R., whom prosecutors described as an agent for an employee of China's Ministry of State Security (MSS).

Through their company, the couple concluded a co-operation agreement with a German university, part of which involved preparing a study for a Chinese contractual partner on machine parts that can be used for the operation of powerful marine engines such as combat ships, the statement said.

The Chinese contract partner was the MSS employee from whom Thomas R. received his orders, it added.

The suspects also purchased a special laser from Germany on behalf of and with payment from the MSS and exported it to China without authorisation, according to the prosecutors.

German Chancellor Olaf Scholz was in China last week to press the case for Beijing to guarantee German firms equal market access, while also conveying concerns in Europe about Beijing's economic policies and support for Russia.

The Chinese embassy in Berlin did not immediately respond to a request for comment.

(Reporting by Andrey Sychev, Editing by Rachel More and Matthias Williams)