By Friederike Heine and Paolo Laudani
GDANSK/BERLIN (Reuters) - German chemicals group Covestro and Swiss cement maker Holcim (SIX:HOLN) said on Friday they were helping Germany probe suspected espionage after drones were flown over industrial sites.
Prosecutors said on Thursday they had opened an investigation into repeated drone flights over critical infrastructure in northern Germany that were suspected of spying for sabotage purposes.
The German military's Territorial Command, responsible for domestic military bases, said it had complied with a police request to provide radar data on the suspicious drone flights.
Covestro and Holcim are among a group of chemical, energy and logistics companies that have operations in the ChemCoast Park industrial area in Brunsbuettel in the northern state of Schleswig-Holstein.
"At the request of the authorities, we are providing support in their investigations," Covestro said in an emailed response to Reuters.
Holcim said it was in close dialogue with the authorities and had not taken any further measures.
German oil and gas company Wintershall Dea said it was not aware of any drone flights over its extraction operations in Brunsbuettel, but added it was monitoring the situation closely.
The prosecutor's office declined to provide updates on the investigation on Friday, while criminal and state police did not reply to requests for comment.
On Thursday, Bild newspaper cited state criminal police as saying the drones in question were likely to have been Russian Orlan-10s, which have a range of 500-600 kilometres (310-372 miles) and can fly at over 100 kph (62 mph).
Germany, one of Ukraine's biggest suppliers of military aid since Russia's invasion in 2022, has been on increased alert over sabotage activity. Earlier this month authorities sealed off a military base near Cologne on suspicion of contaminated tap water that turned out to be false.
In April, two German-Russian nationals were arrested on suspicion of plotting sabotage attacks, in what officials called a serious effort to undermine military support for Ukraine.