The Kremlin on Thursday endorsed a blog post by the U.S. investigative journalist Seymour Hersh that alleges the United States was behind the sabotage of the Nord Stream gas pipelines, saying it should be taken seriously.
The self-published article claimed that the U.S. Navy helped Norway plant explosives on the pipelines running under the Baltic Sea between Russia and Germany.
Both Washington and Oslo denied the claims.
Kremlin spokesman Dmitry Peskov said it was a "very serious" article that had a "deep analysis."
"It would be unfair not to give it attention," he said. "Unfortunately, the article was not widely disseminated in the Western media, which cannot but cause our surprise."
Peskov said Moscow had information "on the involvement of the Anglo-Saxons in the organization of this act of sabotage," a claim Russia has made repeatedly but without providing any evidence publicly.
Western countries have blamed the September pipeline explosions on Russia, but Moscow has accused the West of sabotage.
Hersh, an 85-year-old veteran investigative journalist, has in recent years been accused of spreading conspiracy theories.