German Defense Minister Boris Pistorius warned against jumping to conclusions on Wednesday after new information emerged about the Nord Stream gas pipeline explosions, with a Berlin official suggesting the attack may have been a “false flag” operation aimed at discrediting Ukraine, Reuters reported.

Pistorius’ comments came after The New York Times reported on Tuesday, citing information verified by US officials, that explosions that disabled pipelines built to carry Russian gas to Germany may be behind pro-Ukrainian group.

A separate report by German public broadcaster ARD and newspaper Zeit said German authorities were able to identify the device used in the sabotage mission. According to sources, a group of 5 men and a woman rented a yacht from a company in Poland owned by citizens of Ukraine.

The group allegedly did this using fake passports, their true citizenships not reliably known.

“We have to make a clear distinction between whether this was a Ukrainian group, whether it could have happened at the behest of Ukraine, or whether it was a pro-Ukrainian group that acted without the government’s knowledge,” Boris Pistorius said on Wednesday.

“But I warn against jumping to conclusions,” he said in Stockholm, where he is attending a meeting of European Union defense ministers.

Pistorius also said it was “equally likely” that the attack was the result of a “false flag” operation aimed at blaming Ukraine.

Ukraine denies its involvement in the explosions on the Nord Stream gas pipeline

The New York Times on Tuesday noted that there is no evidence of a connection between the attack and the government of Ukraine or other structures of the Ukrainian state.

Several senior Ukrainian officials have already said Kyiv had nothing to do with the attack, reaffirming their position after the explosions were discovered last September.

Ukraine’s Defense Minister Oleksiy Reznikov, who is in Sweden after being invited to attend a summit of EU defense ministers, said on Wednesday that the media reports were “a bit strange”.

“This is like a compliment to our special forces. But this was not our activity,” he said, once again stressing that the Ukrainian authorities had nothing to do with the explosions on Gazprom’s pipelines in the Baltic Sea.

When asked by journalists about this, Reznikov said that he was not worried that this information in the media could weaken the support of his country from the West.

Both Nord Stream gas pipelines were not operating at the time of the explosions. Nord Stream 2 was halted after Germany suspended approval for the project on February 22, and Nord Stream 1 was shut down by Russia in early September.