German prosecutors issued an arrest warrant earlier this summer in an investigation into the undersea explosions in 2022 that damaged the Nord Stream gas pipelines between Russia and Germany, German media outlets have reported and a Polish government spokesperson has confirmed.

German public broadcaster ARD, the daily Sueddeutsche Zeitung and the weekly Die Zeit said in a joint report Wednesday that federal prosecutors obtained an arrest warrant in June against a Ukrainian man believed to have resided until recently in Poland. The reports, which did not cite sources, identified the man as Volodymyr Z.

German government spokesperson Wolfgang Büchner declined to comment on the reported warrant Wednesday, referring questions to federal prosecutors. But he said that clearing up what happened has the "highest priority."

Polish National Public Prosecutor's Office spokesperson Anna Adamiak confirmed to Reuters that German authorities sent a European arrest warrant to the District Prosecutor's Office in Warsaw in June in the case of Ukrainian citizen Volodymyr Z., in connection with proceedings conducted against him in Germany.

Adamiak said Polish officials believe the man, a diver, is no longer in the country, having crossed the border into Ukraine in July. As to why he wasn't detained at the border crossing, she told Reuters that German authorities did not specify what he was accused of, "which meant that the Polish Border Guard had no knowledge and no grounds" to detain him.

According to the German media reports, arrest warrants have not yet been issued for another man and a woman — Ukrainian diving instructors — who have been identified as part of the probe.

Pipelines built to carry Russian gas

Explosions on Sept. 26, 2022, damaged the pipelines, which were built to carry Russian natural gas to Germany under the Baltic Sea.

The blasts happened as Europe attempted to wean itself off Russian energy sources following the Kremlin's full-scale invasion of Ukraine in February 2022. They ruptured the Nord Stream 1 pipeline, which was Russia's main natural gas supply route to Germany until Russia cut off supplies at the end of August 2022.

They also damaged the Nord Stream 2 pipeline, which never entered service because Germany suspended its certification process shortly before Russia invaded Ukraine.

WATCH l Explosives used in attack, Swedish officials say:

Nord Stream pipelines show evidence of damage from explosives, Sweden says

Sweden says its investigators have found traces of explosives at the site of damaged Nord Stream 1 and 2 gas pipelines in the Baltic Sea and confirms sabotage had taken place. The pipelines that run along the seabed from Russia to Germany were damaged from powerful explosions in late September, sparking a probe by a number of countries.

Russia has accused the U.S. of staging the explosions, a charge Washington denies. The pipelines were long a target of criticism by the U.S. and some of its allies, who warned that they posed a risk to Europe's energy security by increasing dependence on Russian gas.

Who was responsible for the sabotage remains a mystery and investigators have been tight-lipped about their findings so far.

Last known probe of attack

Swedish and Danish authorities closed their investigations in February, leaving the German prosecutors' case as the sole probe.

In March 2023, German media reported that a pro-Ukraine group was involved in the sabotage. Ukraine rejected suggestions it might have ordered the attack and German officials voiced caution over the accusation.

Officials said last year that investigators found traces of undersea explosives in samples taken from a yacht that was searched as part of the probe.