Police arrested he 55-year-old man on Tuesday in a small village in northern Greece, said the source. He will stay in custody until a court decides on whether he can be extradited to Germany.

He and another man, from Romania, are suspected of having tried to sabotage the ships in the northern German port of Hamburg in 2025, said Eurojust, the EU Agency for Criminal Justice Cooperation.

"This includes dumping more than 20 kilogrammes of abrasive gravel into the engine block of German navy ships, puncturing the fresh water supply lines, removing fuel tank caps, and deactivating electronic safety switches," said Eurojust.

Both were seasonal workers there.

In the Greek raid, officers seized a computer, six mobile phones, three USB sticks, a SIM card, a hard drive, and 19 bank books at his home, said Greek police sources.

The materials were handed over to the German authorities.

According to a police source, the 55-year-old Greek man and his family are Muslims from the Pomak minority.

The authorities in Germany, Romania, and Greece collaborated to arrest the two men, while investigations into the attempted sabotage continue.