But the statements did not address the key question of the months-old mystery of the blasts that set the continent on edge: how the explosives were placed on the underwater pipelines and who might be responsible.

European leaders blame Russian ‘sabotage’ after Nord Stream explosions

The prosecutor’s office said the ongoing investigation will determine whether any suspects will be identified, while the security service said “the advanced analysis work is still in progress — the aim is to draw more definitive conclusions.”

The explosions in late September rocked a key pipeline that carried natural gas from Russia to Europe at a time when Moscow is using energy as leverage in retaliation for Western sanctions over the Kremlin’s war in Ukraine.

European officials were quick to call the incident “sabotage,” and some have cast blame on Russia, although multiple investigations are underway, with Danish and German authorities also collecting evidence.

“These are deliberate actions, not an accident,” Danish Prime Minister Mette Frederiksen told reporters Sept. 27 soon after the blasts. “The situation is as serious as it gets.”

Russia denied responsibility. The Kremlin is “extremely concerned,” spokesman Dmitry Peskov said the same day.

Nord Stream spill could be biggest methane leak ever but not catastrophic

Although the explosions initially raised fear of shortages, the impact on European supply was limited, mostly because the European Union had already started weaning itself off Russian energy.

The energy crisis pushed European countries to build up reserves and find alternative sources of supplies ahead of the winter, as Russia cut off flows and energy prices rose. E.U. countries have also rushed to tighten security around key infrastructure and boost naval operations since the pipeline explosions.

The damage from the blasts hit part of Nord Stream 1, which was a major route for Russian natural gas to Germany, Poland and other European nations.

Russia stopped the gas flow through Nord Stream 1 earlier this year, citing technical problems, while European leaders accused Moscow of trying to “blackmail” countries that have sent weapons to Ukraine to help fend off Russian forces.

Another leak was part of the newer Nord Stream 2 pipeline project, which Germany froze earlier in the conflict shortly before the pipeline was set to go online.

Francis reported from London. Helier Cheung contributed to this report.