This aerial photo released by the Danish Ministry of Defense on Sept. 27, 2022 shows the Nord Stream gas pipeline leak site. (Danish Defense Ministry/Handout via Xinhua)

A leading European analyst told Xinhua on Tuesday potential proof of U.S. involvement would impact the way each side of the Ukraine crisis is viewed internationally.

ROME, Feb. 22 (Xinhua) -- Three European countries looking into the details surrounding last September's Nord Stream pipelines explosion said on Tuesday they are not sure when their probes will be complete, even as allegations swirl that the United States may have been responsible for the underwater blast.

A leading European analyst told Xinhua on Tuesday potential proof of U.S. involvement would impact the way each side of the Ukraine crisis is viewed internationally.

Davide Tabarelli, a professor of industrial engineering at the University of Bologna and president of Nomisma Energia, an energy research consultancy, said rumors of possible U.S. sabotage were out even earlier than the latest debate.

"We have heard rumors of a possible involvement by the United States for several weeks, well before the latest accusations," Tabarelli told Xinhua.

Aerial photo provided by the Swedish Coast Guard on Sept. 28, 2022 shows a gas leak on the Nord Stream 1 pipeline.(The Swedish Coast Guard/Handout via Xinhua)

The Nord Stream pipelines, which transported natural gas from Russia to European markets via Germany, were severely damaged last September after blasts in the Baltic Sea.

One pipeline, Nord Stream 1, was in operation at the time of the explosion and Nord Stream 2, though had not been operational, was filled with gas.

Recent allegations from Pulitzer Prize-winning U.S. journalist Seymour Hersh and others said that the attack had been carried out by divers from the U.S. Navy.

Hersh, who has pledged to share more information from his investigation soon, said explosives were planted during exercises involving countries allied within the North Atlantic Treaty Organization (NATO) around three months prior to the blast and only detonated in September.

This photo taken on Jan. 20, 2023 shows the White House in Washington, D.C., the United States.(Xinhua/Liu Jie)

U.S. National Security Council Spokesman John Kirby on Monday dismissed allegations of U.S. involvement in the explosions.

Russia requested that the United Nations (UN) Security Council call for an international investigation into the explosion. On Tuesday, the Security Council heatedly debated Russia's request for a UN-led inquiry into the incident.

An investigation by the UN Security Council into the explosions that blew up the Nord Stream natural gas pipelines in September 2022 is a high global priority, said Jeffrey Sachs, a world-renowned economist, on Tuesday.

"The destruction of the Nord Stream pipelines on Sept. 26, 2022, constitutes an act of international terrorism and represents a threat to the peace," Sachs told the Security Council in a briefing.

Photo taken on April 28, 2022 shows the office of Russia's energy giant Gazprom in Moscow, Russia. (Photo by Alexander Zemlianichenko Jr/Xinhua)

China supports speeding up the investigation into the Nord Stream explosions so as to swiftly find out the truth, Foreign Ministry Spokesperson Wang Wenbin said on Wednesday. Noting the Nord Stream gas pipelines are major transboundary infrastructure and energy transportation arteries, Wang said the explosions had a major negative impact on the global energy market and the ecological environment.

In a joint letter to the Security Council, Denmark, Sweden and Germany -- the three countries closest geographically to the part of the Baltic Sea where the explosions took place -- said that their investigations were ongoing and that it was unclear when they would conclude.

Noting the "consequences as concerns greenhouse gas emissions are substantial and worrisome," the letter reiterated that "deliberate acts, such as those committed against the Nord Stream pipelines, are unacceptable, endanger international security and give cause for our deep concern."

This aerial photo provided by the Swedish Coast Guard on Sept. 28, 2022 shows the fourth leak on Nord Stream 2 pipeline in Sweden's exclusive economic zone. (The Swedish Coast Guard/Handout via Xinhua)

Croatian security expert Mirko Vukobratovic told Xinhua on Tuesday that the alleged involvement of the U.S. Navy in the September 2022 Nord Stream explosions, is "not impossible" because the United States has benefited the most from the incident.

编辑：韩睿