Denmark extended an invitation to the Nord Stream 2 pipeline's Russian-controlled operator to assist in the recovery of an unexplained object discovered close to the Baltic Sea's sole surviving intact gas pipeline.

Russian President Vladimir Putin, who unmasked the discovery of the object earlier this month, said experts acknowledge that it could be a signal antenna to activate an explosive in that part of the pipeline. 

German, Swedish, and Danish authorities are reportedly investigating the undersea explosions that sparked four leaks on the two Nord Stream pipelines in the Baltic Sea in September, seven months after the war in Ukraine started.

The Danish energy agency publicized a photo late Thursday of the cylindrical object standing near the Nord Stream 2 pipeline at the bottom of the sea.

In a statement, the agency said it is "possible" that the object is a maritime smoke buoy, 40 centimeters (16 inches) tall and 10 cm (four inches) wide, and that it "does not pose an immediate safety risk."

"With a view to further clarifying the nature of the object, Danish authorities have decided to salvage the object with assistance from the Danish Defence," it added.

The organization noted that before beginning the recovery effort, it was still awaiting word from the pipeline's owner.

The twin pipelines are majority owned by the Russian energy behemoth Gazprom, with the remaining shares held by German, Dutch, and French firms.

German authorities claimed earlier this month that a ship suspected of carrying the explosives used in the blasts was searched in January.

Confirmation of the searches came after the New York Times claimed that US officials had seen new intelligence indicating that a "pro-Ukrainian group" was responsible for the sabotage.

The Ukrainian government rebuffed any involvement in the action, while the Kremlin rejected the Times report as a "diversion".

It is worth noting that Copenhagen has lately forbidden Moscow from partaking in the investigation of the Nord Stream pipelines’ explosion.

Russian Foreign Ministry Spokesperson Maria Zakharova, announcing Moscow’s stance, described Copenhagen's decision as a "fraud" and "scam".

Earlier, Russian President Vladimir Putin revealed that Russia had offered the Danish authorities to form an international group of experts to investigate the Nord Stream explosions but was met with a firm refusal.

The Nord Stream 1 and 2 pipelines connecting Russia and Germany under the Baltic Sea were attacked by a series of unexplained explosions last September. Russia had since described it as a case of state terrorism.

This month, Putin said that last year's Nord Stream gas pipeline explosion had been carried out on a "state level", dismissing claims which suggest that an autonomous pro-Ukraine organization was responsible for the blast as "complete nonsense".

Read more: West may be concealing Nord Stream probe findings: French General

After American investigative journalist Seymour Hersh published a shocking article in February in which he said that the US and Norway were behind the bombing of the Nord Stream pipelines, the former Head of the French Military Mission at the United Nations General Dominique Trinquand said, in early March, that the West may be purposefully suppressing the findings of investigations into the Nord Stream blasts.

Read next: Seymour Hersh: Biden bombed Nord Stream, 'everyone's on our hit list'