"Powerful explosions" left gaping holes in the Nord Stream pipelines, investigators said as they look to see whether sabotage is to blame for leaks found last month.
Four holes were found in the Nord Stream 1 and 2 pipelines on September 26. With Europe already rife with concerns about energy supplies this winter amid supply cuts from Russia as it wages war against Ukraine, world leaders -- including from Russia -- have called the damage sabotage.
Copenhagen police said on October 17 that they were investigating the damage with Denmark's Security and Intelligence Service after seismologists in the country said they had registered tremors -- which did not resemble those seen during earthquakes -- in the vicinity of the leaks measuring as much as 2.3 on the Richter scale.
"It is still too early to say anything about the framework under which the international cooperation with e.g. Sweden and Germany will run, as it depends on several factors," the Copenhagen police said in a statement.
Swedish investigators have already said they found two holes in the pipeline.
The Swedish daily Expressen published video and pictures on October 17 showing metal and a wide-open pipeline with at least 50 meters missing in murky waters at the bottom of the Baltic Sea.
"It is only an extreme force that can bend metal that thick in the way we are seeing," Trond Larsen, who piloted the submersible drone which captured the video, told Expressen.
The leaks along the pipelines in the Swedish and Danish exclusive economic zones in the Baltic Sea lasted about a week, discharging huge amounts of methane into the air.
The pipelines -- built to carry Russian natural gas supplied by Kremlin-controlled energy giant Gazprom to Germany -- were filled with Russian gas at the time of the explosions, but were not operational due to the consequences of the war in Ukraine and tensions with Russia.
Russia earlier this year slashed exports through Nord Stream 1, claiming Western sanctions on equipment and services impaired its ability to maintain the pipeline. Nord Stream 2, the newer pipeline, was never put into operation.
The Kremlin claimed on October 17 that the exclusion of Russia from the investigation was further evidence that the West is looking "to put the blame on Russia" for the accident.