Sept. 27 (UPI) — Ukraine on Tuesday accused Russia of sabotaging the Nord Stream pipelines to create a panic ahead of the winter season to push the European Union for its support of Kyiv.

Mykhaylo Podolyak, an adviser to Ukrainian President Volodymyr Zelensky charged that damage to Nord Stream 1 and 2 was “an act of aggression.”

“‘Gas leak’ from NS-1 is nothing more [than] a terrorist attack planned by Russia and an act of aggression toward the [European Union],” Podolyak said on Twitter. “[Russia] wants to destabilize the economic situation in Europe and cause pre-winter panic. The best response and security investment — tanks for [Ukraine], especially German ones.”

Podolyak’s comments come as Sweden’s National Seismology Center said there was an underwater blast in the area of the pipes at the time they lost pressure.

“There is no doubt that these were explosions,” said Bjorn Lund of Sweden’s National Seismology Centre, according to BBC News.

The pipelines are 745 miles long under the Baltic Sea from the Russian coast near St. Petersburg to northeastern Germany.

German officials on Tuesday continued to investigate what caused leaks. The pipelines — Nord Stream 1 and Nord Stream 2, had not been active but were still filled with natural gas when authorities noticed a sharp drop in pressure on Monday.

“We are currently in contact with the authorities concerned to clarify the matter,” Germany said in a translated statement. “We still have no clarity about the causes and the exact facts. It is also still being clarified whether the incident occurred in German territorial waters.

“Specifically, the exchange between BMWK, the network operator, the Federal Network Agency, the Federal Police and the local mining authority in Stralsund as well as the responsible state ministries in Mecklenburg-Western Pomerania.”

A statement from the Danish Maritime Authority said it discovered a leak in the Nord Stream 2 pipeline in their part of the Baltic Sea.

“The preliminary assessment indicates that a leak has occurred from one of the two Nord Stream 2 pipelines in the Danish area Southeast of Dueodde at Bornholm … from where natural gas is leaking,” the Danish statement said.

“The Danish Maritime Authority has released a navigational warning and established a prohibitive zone within five nautical miles of the pipeline, as it is dangerous for naval traffic.”

The maritime authority added that there were not any security risks related to the leak outside of the prohibitive zone and that the incident was not expected to impact the security of the Danish gas supply.

The operator of Nord Stream 1 confirmed later a pressure drop had been detected and confirmed by the German economy ministry.

The pipelines have been part of a confrontation between Russia and Europe connected with Moscow’s invasion of Ukraine. Russia began withholding the natural gas that for decades it had abundantly sent to Europe because of sanctions levied by the West over the war.