Ukraine army head authorised Nord Stream blasts: report

The sabotage of the Nord Stream gas pipelines two years ago was authorised by the Ukrainian army's then-commander-in-chief, the German magazine Spiegel reports.

The operation in the Baltic Sea cost nearly $US300,000 ($A439,600) and was privately funded but was presented to Valerii Zaluzhnyi for authorisation, the magazine reported citing its own research.

President Volodymyr Zelenskiy was reportedly not informed in advance.

The two pipelines carried Russian gas to Germany although one was not yet operational.

Ukraine and the United States had lobbied against the pipelines.

Zaluzhnyi, who is now Ukrainian ambassador to the United Kingdom, told the Wall Street Journal that he knew nothing about such an operation.

In August, the newspaper reported that Zaluzhnyi was involved in the action.

Zelenskiy has always denied his government's involvement in the sabotage operations.

Spiegel also reported that the sabotage team consisted of several Ukrainian divers, nearly all of them civilians.

The operation was reportedly planned and led by former Ukrainian intelligence officer Roman Chervinsky.

Chervinsky had already denied his involvement according to stories in the Washington Post and Spiegel last year.

In late September 2022, several explosions damaged and interrupted the two Nord Stream 1 and 2 gas pipelines.

The detonations were detected near the Danish Baltic Sea island of Bornholm.

Russian natural gas had been flowing to Germany through Nord Stream 1.

Nord Stream 2 was not yet operational due to the Russia's war against Ukraine and subsequent political debates.

In mid-August of this year, it was revealed that Germany's top public prosecutor was seeking a Ukrainian man who is believed to have fled from Poland to his homeland.

The German newspapers Die Zeit and the Süddeutsche Zeitung, along with public broadcaster ARD, reported that the man, along with two other Ukrainian citizens are suspected of being involved in the explosions.

They might have attached the explosives to the pipelines as divers, the reports said.

The German Federal Prosecutor's office declined to comment on the media reports when asked.