The United States must be held accountable and give a responsible explanation to the world if it did attack the Nord Stream pipelines, said Foreign Ministry spokesman Wang Wenbin at a press conference in Beijing on Tuesday. In an article published by British newspaper The Times recently, Seymour Hersh, an American investigative journalist, exposed that the Nord Stream pipelines transporting gas from Russia to Europe were blown up secretly by US intelligence agencies and military personnel in September last year. "The Nord Stream gas pipelines are vital transnational infrastructure. The explosions have had a serious impact on the global energy market and ecological environment. If the American investigative journalist Hersh is telling the truth and it was the US who attacked the pipelines, the act is clearly unacceptable and must be answered for. The US owes the world a responsible explanation," Wang said. "What we want to ask is why those media outlets that have always been claiming themselves to be free, professional and fair have made few reports on the latest Nord Stream investigation and such a major incident as the train accident that caused chemical leak which is threatening American people's life and safety? As far as we know, it is not the first time that this has happened," Wang said. The leaks of Nord Stream 1 and 2 pipelines happened on Sept 26 when a flurry of detonations triggered four gas leaks at four locations on the pipelines, sending gas spewing to the surface of the Baltic Sea.