Serhii Kuznetsov (C) was pictured in court on Wednesday after his anonymity order was lifted

A Ukrainian man has gone on trial in Hamburg accused of blowing up Russia's Nord Stream gas pipelines to Germany, four years after one of the most dramatic acts of sabotage in modern European history.

Prosecutors say Serhii Kuznetsov played a leading role in a team of saboteurs that destroyed the pipelines, accusing him of a war crime. His defence has called for the case to be dismissed.

The case is highly sensitive in Germany, seen as one of Ukraine's closest allies since Russia launched its full-scale invasion in February 2022, seven months before the attacks took place.

Extradited to Germany last year, Kuznetsov denies the charges, as does a second suspect who is fighting extradition from Croatia.

Kuznetsov became the first suspect to go on trial for the blasts on Wednesday morning, and a packed public gallery looked on as he entered the courtroom, appearing relaxed.

He even smiled at times, including during initial exchanges where he spoke to confirm personal details such as his name and place of birth.

He had previously only been identified by German prosecutors as Serhii K and pictured with his face blurred, before the court lifted an anonymity order on Wednesday.

Kuznetsov, 50, wore a pair of headphones and appeared to listen intently to a translation of proceedings in Ukrainian, as the prosecution read out the charges against him, of ordering divers and an explosive expert to attack civilian infrastructure.

The defence outlined their case, telling the court that only circumstantial evidence had emerged in the four years since the Nord Stream blasts.

They argued that as a soldier the defendant was bound to secrecy, and therefore he could not have a fair trial in which he spoke freely.

Prosecutors argue the case falls under Germany's code of crimes against international law as a war crime, as an "attack by military means against civilian objects".

One of Kuznetsov's lawyers said his extradition to Germany was flawed as no mention had been made at the time of the war crime allegation.

Kuznetsov was extradited to Germany from Italy late last year

In the months after explosives destroyed three of the four gas pipelines in the Baltic Sea off the island of Bornholm on 26 September 2022, Western suspicion looked towards Moscow without directly apportioning blame.

Russia had already shut off the flow of gas to Germany in Nord Stream 1 weeks before the attack, and Nord Stream 2 had never been turned on. Berlin had frozen the multi-billion dollar project shortly before the invasion and there were reports of suspicious Russian naval movements before the blasts.

As investigators from Sweden, Denmark and Germany tried to find out who carried out the attack, Russia's Vladimir Putin accused the US and its UK allies, blaming "the Anglo-Saxons" - which they denied.

Eventually, after Denmark and Sweden shut down their inquiries, German prosecutors focused on a group of deep-sea divers who had rented a yacht called the Andromeda in the northern German port of Rostock.

They said later that "traces of subsea explosives were found in the samples taken from the boat".

Despite the strain on relations with Kyiv, German prosecutors pressed ahead with the case, and in January 2025 the German federal court of justice ruled that it fell within German territorial jurisdiction, external and prosecutors had a responsibility to act as it involved "undermining [Germany's] internal security".

Ukraine's Volodymyr Zelensky has always maintained that Ukraine had "nothing to do with [the Nord Stream blasts]", although in their indictment German prosecutors allege the saboteurs conceived the plot "acting by order of Ukrainian state agencies".

Nord Stream trial: How German police followed the evidence - to Ukraine

The case has highlighted differences of opinion on the trial in Kyiv and Berlin.

Oleksandr Merezhko, who chairs the Foreign Affairs Committee in the Ukrainian parliament, points out that the blasts took place during a time of war with Russia and "Nord Stream 2 was nothing but a tool used by Russia in order to get prepared for the war".

He told the BBC they had no confirmation of the German account: "It's one of the versions."

However, Stefan Meister, of the German Council on Foreign Relations, says successive chancellors in Berlin have done their best to remove the politics from the case.

"They tried to make not a big story out of it, not to give it too much attention, to give it to the institutions, to the judiciary that they will deal with it. This is not a political case. So they tried to depoliticise it," he explained.

Three of the four Nord Stream pipelines were ruptured by explosions in September 2022

In August 2025, Kuznetsov was arrested after checking into a hotel near the Italian Adriatic resort of Rimini, by police acting under a European arrest warrant issued by federal prosecutors in Germany.

After several weeks of court battles fighting extradition, when his surname emerged in court documents, Kuznetsov was transferred to Germany late last year.

German prosecutors allege that in 2022 he was a serving officer in the Ukrainian army, external, and he had led a group of professional divers, a boat captain and an explosives expert.

While his legal fight was going on in Italy, another Ukrainian man called Volodymyr Zhuravlov successfully challenged Germany's extradition bid in a Polish court.

In a ruling very different from Italy's Supreme Court, the Polish judge ordered Zhuravlov's release in October 2025, stating that the attack on the pipelines was not unlawful, and if Ukraine had organised an armed mission it was "justified, rational and just".

Although he was released by the court in Warsaw, he was arrested last August in Croatia on suspicion of being a suspect who "participated in the dives necessary" for the sabotage.

Last month, Croatia approved his extradition, although it is not clear when that will happen, and if his case could become part of the Hamburg trial.

Despite the difficult nature of the case for Kyiv and Berlin, Ukrainian MP Oleksandr Merezhko does not believe it will spoil relations as "it's in the best national interests of Germany to continue to support us".

Polish judge refuses to extradite Ukrainian Nord Stream blasts suspect

A journey to the site of the Nord Stream explosions