U.S. officials believe explosions last year along the Nord Stream pipelines, a multi-billion infrastructure project designed to carry Russian gas to Germany, were a deliberate attack. 

Earlier this month, officials said U.S. intelligence suggested that a pro-Ukrainian group was behind the attack. On Wednesday, National Security Council spokesman John Kirby said there are three investigations being conducted on the matter. 

"We still do believe it was an act of sabotage," he told reporters during a White House press briefing. 

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He noted the United States "was not involved in any way," contrary to some press reports. 

The pipelines were condemned by the West as a national security threat. It allowed Russia to sell gas more easily to Europe despite sanctions over its invasion of Ukraine. 

When asked about the attack earlier this month, Kirby only referred to the separate investigations being conducted by Germany, Sweden and Denmark. 

"So, I'm just not going to get ahead of that investigative work and I would have to refer you to each of those European countries to comment on their investigations," he said at the time. 

According to the New York Times, a review of the newly collected intelligence indicated the perpetrators were likely opponents of Russian President Vladimir Putin, "but does not specify the members of the group, or who directed or paid for the operation." 

The White House had previously dismissed a blog post from investigative journalist Seymour Hersh claiming President Biden had directed the attack. The White House, the CIA and NSC all said the post was "utterly false and complete fiction."

Fox News' Danielle Wallace contributed to this report.