Sweden’s Navy has confirmed that armed personnel in military uniforms are aboard oil tankers belonging to Russia’s shadow fleet operating in the Baltic Sea, according to a report by SVT Nyheter, Sweden’s public-service news organization.

The confirmation comes amid reports that Russia has been conducting an intensified military operation in the Baltic Sea, believed to be focused on protecting the country’s shadow fleet—older oil tankers used to circumvent Western sanctions against Russian oil.

According to the Swedish Navy’s Chief of Operations Marko Petkovic, the uniformed and armed personnel are believed to come from private security companies. “We have seen and received information that there are uniformed personnel aboard some of these shadow fleet vessels,” Petkovic stated.

The Russian military effort extends beyond personnel aboard tankers. The Russian Navy has established “a fairly constant presence” in several specific areas adjacent to shipping lanes in the Baltic Sea, the Gulf of Finland, and surrounding waters, according to the SVT report. “Russian naval presence has become more permanent and present in large parts of the Baltic Sea,” Petkovic noted, adding that the Russian Navy “appears to be operating there in some way in support of this shadow fleet”.

Information about military-clad personnel aboard shadow fleet vessels has circulated in recent months, most recently reported by Danish publication Danwatch, where pilots testified to threatening situations.

In March, an investigation by High North News uncovered that Russia’s Federal Security Service (FSB) has methodically asserted control over the Yamal LNG Arc7 ice-class LNG carrier fleet—pivotal for transporting Russian liquefied natural gas from the Sabetta terminal to Europe and Asia—by systematically removing Western officers and replacing them with Russian personnel, significantly reducing foreign influence aboard the vessels since 2022. According to former crew interviewed and internal documents, the FSB employed intimidation, interrogation, and an onboard informant network to push out Western captains and senior officers, aiming to cement Russian operational control.

Daniel Stenling, deputy chief of operations at Sweden’s Coast Guard, confirmed that Russian naval vessels have been increasingly observed in strategic offshore locations. While the Coast Guard has not directly observed the armed personnel, Stenling emphasized the significance of the shadow fleet to Russia’s economy and Moscow’s invasion of the Ukraine. “We know that this is such an important activity for Russia, so we expect that various security measures have been taken and such things could very well be considered there,” he said.