Investigators in northern Germany confirmed on Thursday that they were investigating suspicious drone activity over an industrial park in Brunsbüttel, following media reports about the case.

"The Flensburg public prosecutors office confirms the launching of an investigation due to the suspicion of espionage activity for sabotage purposes, in connection with repeated drone flights over critical infrastructure in Schleswig-Holstein," a spokesman for prosecutors in nearby Flensburg told the AFP news agency, issuing similar comments to others.

Coastal industrial park, and site of LNG terminal designed to help replace Russian gas

The industrial park around the harbor in Brunsbüttel, northwest of Hamburg near the mouth of the River Elbe where it enters the North Sea, is home to a new floating liquid natural gas (LNG) terminal.

This was set up with government support in response to Russia's invasion of Ukraine and amid Germany's hurried efforts to source energy imports from elsewhere. Plans are in place to replace it with a permanent facility at the same site. 

The area houses several chemicals companies and a decommissioned nuclear power plant that's being dismantled after it was shut off in 2011. 

It's also the entry point to the Kiel Canal, or Nord-Ostsee Kanal in German, that links the North Sea at Brunsbüttel to the Baltic Sea at Kiel-Holtenau, used by roughly 30,000 ships per year.

Prior reports suggest police suspect military drone activity

Prior to Thursday's limited comments from prosecutors in Flensburg, two of Germany's most-read news outlets, Bild and Spiegel, had both reported on the case. 

They said that repeated drone flights over the area had been observed since August 8. 

The reports cited police specialists as theorizing that the drones, with high flight speeds, could be Russian military espionage vehicles. 

Spiegel reported that police drones, which tried to follow the mystery observers back out to sea, had not been able to match flight speeds in the region of 100 kilometers per hour (around 60 miles per hour). As a result, police had reportedly turned to the Bundeswehr military for help. 

A spokesman for the German Defense Ministry told the German news agency DPA on Thursday that the Bundeswehr had been providing radar and other data to police, so they could better investigate the case. 

Germany has been on alert about potential Russian espionage or even sabotage in recent months, which was most visible recently with a series of security scares at Bundeswehr and NATO military facilities in the country. These led to an investigation, but then also to authorities issuing the all-clear.

msh/ab (AFP, dpa, Reuters)