A Greek national has reportedly been arrested as a suspect for attempting to sabotage multiple German warships in Hamburg.

According to German authorities, the 54-year-old Greek was apprehended along with a 37-year-old Romanian suspect. Both were shipyard workers in Hamburg and had reportedly attempted to sabotage ships intended for the German Navy.

As the German media outlet Bild reports, the two men had poured abrasive gravel inside the engine of the corvette “Emden”. The report claims they had also damaged freshwater pumps, removed fuel tank caps, and deactivated electronic safety switches.

German police were alerted to the sabotage during an inspection of the vessel shortly before it was about to sail for the port of Kiel.

Bild reports the police operation was coordinated by Eurojust, the Hague-based European Union Agency for Criminal Justice Cooperation.

According to the German prosecutor in charge of the case, the two had collaborated but had also worked alone on occasion.

Vice Admiral Jan Christian Kaack said the saboteurs had deliberately caused damage to more than one naval vessel, confirming a pattern rather than an isolated incident.

“There was destruction — in other words, sabotage — on more than one ship,” Kaack said during the “Navy Talks” event in Berlin. He added that appropriate security measures had since been implemented at shipyards in response.

At the time, German media outlets WDR, NDR and Süddeutsche Zeitung reported that the corvette Emden had been targeted. The vessel was built at the Blohm+Voss shipyard in Hamburg but had not yet been delivered to the German navy when the suspected sabotage occurred.