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)

BEIJING - China expressed concern on Friday over reports of US involvement in the sabotage of the Nord Stream gas pipelines in September last year.

If the reports from investigative journalist Seymour Hersh on US involvement in the explosions at the pipelines are true, the US owes the world a responsible explanation, Chinese Foreign Ministry spokesperson Mao Ning said.

According to Hersh, a Pulitzer Prize winner, US divers installed explosives under the Nord Stream pipelines during the NATO military exercise BALTOPS (Baltic Operations) in the summer of 2022, and detonated them in September.

ALSO READ: Kremlin says those behind Nord Stream blasts must be punished

Mao told a daily news briefing that the Nord Stream gas pipelines are vital transnational infrastructure, and the explosions have had a serious impact on the global energy market and ecological environment.

"If Hersh is telling the truth, what he revealed is clearly unacceptable and must be answered for," Mao said.