New intelligence reviewed by U.S. officials suggests that a pro-Ukraine group – likely comprised of Ukrainians or Russians – attacked the Nord Stream gas pipelines in September, but there are no firm conclusions, the New York Times reported on Tuesday.

There was no evidence that Ukrainian President Volodymyr Zelenskyy or other Ukrainian government officials were behind the attacks which spewed natural gas into the Baltic Sea, the newspaper reported, citing U.S. officials.

The September 26 explosions on the pipelines connecting Russia and Germany occurred in the exclusive economic zones of Sweden and Denmark. Both countries have concluded the blasts were deliberate, but have not said who might be responsible.

The United States and NATO have called the pipeline attacks "an act of sabotage," while Moscow has blamed the West. Neither side has provided evidence.

Denmark, Germany and Sweden said last month that their investigations have not yet concluded. The United States and Britain said on Tuesday they were waiting on those findings.

"We need to let these investigations conclude and only then should we be looking at what follow-on actions might or may not be appropriate," said White House spokesperson John Kirby.

Germany said on Tuesday it had taken note of the New York Times report but that its own investigation had not yet produced results. NATO Secretary-General Jens Stoltenberg and Swedish Prime Minister Ulf Kristersson both declined to comment on the new report during a news conference in Stockholm.

A senior aide to Zelenskyy, Mykhailo Podolyak, said that Kyiv was "absolutely not involved" in the blasts and has no information about what happened.

Russia's Foreign Ministry spokeswoman Maria Zakharova said the media reports on Tuesday underscored the need for Moscow's questions about what happened to be answered. She also accused those responsible for the media leaks of wanting to divert the public's attention and avoid a proper investigation.

German Prosecutors Office Authorities said on Wednesday that they searched a ship suspected of having transported explosives linked to the Nord Stream pipeline explosion, according to Germany's Deutsche Welle News, but no further details were disclosed.

In an article published last month on the U.S. portal Substack, Pulitzer Prize winner Seymour Hersh revealed that the United States partnered with Norway in a top-secret operation in June 2022 to plant remotely triggered explosives that took out three of the four Nord Stream pipelines three months later.

Read more:

Exclusive interview with Seymour Hersh: The U.S. has long feared Russian gas and oil

U.S. blowing up Nord Stream pipelines 'economic war' against EU allies: Swedish expert

(With input from agencies)