Weeks after the US investigative journalist Seymour Hersh said in a report that the United States Navy was involved in the Nord Stream explosions last year, Western mainstream media have remained largely silent, let alone done follow-up reports, experts say.

This, they say, demonstrates the hypocrisy and bias of Western news coverage.

Hersh, a Pulitzer Prize winner renowned in particular for uncovering the My Lai Massacre during the Vietnam War, wrote on the US portal Substack on Feb 8 that the Nord Steam pipelines attacks were orchestrated by the White House. The US Navy and the CIA were also involved, he said, citing an unnamed source.

If true, it could be "a terrorist act" committed by the US government against vital German infrastructure, Stephan Ossenkopp, a German scholar with the think tank Schiller Institute, told CGTN.

The US has dismissed Hersh's allegations as "utterly false and complete fiction". Denmark, Germany and Sweden said on Tuesday that blast inquiries have not yet concluded. Russia has called a United Nations Security Council meeting over the attacks.

US mainstream media have by and large remained silent on Hersh's claims. A week after the revelation, US online news portal Mint-Press reported that the 20 most influential news publications in the US, including CNN, The Wall Street Journal and The Washington Post, have essentially disregarded Hersh's story. Four media outlets gave scant attention to it, such as a report of 100 words or so by Bloomberg.

European outlets including the BBC, The Guardian and most German newspapers have ignored it, the Washington-based online magazine Responsible Statecraft said on Feb 16.

Hersh told the US broadcast Democracy Now!, published on Feb 15, that "I wasn't even thinking of taking a story like this to The New York Times", which he had worked for.

Western mainstream media "intentionally ignores" Hersh's report, said Ding Yifan, a research fellow at the Development Research Center of the State Council's Institute of World Development in Beijing.

"Any story that goes beyond their values and stance will not be published," Ding said. "Misinformation, or even disinformation, abounds in Western media, which is part of their public opinion war, or propaganda war. These are their tactics."

Responsible Statecraft quoted Mark Ames, who interviewed Hersh on the US Radio War Nerd program on Feb 11, as saying: "The corporate media is ignoring Hersh's story because they're deeply invested in the US empire and don't like stories that make the US empire look bad."

However, European media were "caught in a dilemma" on this matter, said Wang Zhen, a research professor of international politics at the Institute of China Studies, Shanghai Academy of Social Sciences.

"Dramatizing the issue will only make Europe, especially Germany, look awkward."