The cutting of the two cables within 48 hours prompted European officials to say Tuesday that they suspect "sabotage" and "hybrid warfare" linked to Russia's invasion of Ukraine -- which the Kremlin on Wednesday rejected as "absurd" and "laughable".

The C-Lion 1 submarine cable connecting Helsinki and the German port of Rostock was cut Monday south of Oland island in Swedish waters, around 700 kilometres (435 miles) from Helsinki.

Early Sunday, another telecoms cable, Arelion, running from the Swedish Baltic Sea island of Gotland to Lithuania, was also damaged.

"The Danish Defence can confirm that we are present in the area near the Chinese ship Yi Peng 3," the military wrote in an email to AFP, adding that it would make no further comment for now.

The cargo ship, owned by Chinese company Ningbo Yipeng Shipping, stopped overnight Tuesday to Wednesday in the Kattegat strait between Denmark and southwestern Sweden, according to the tracking site Marinetraffic.

- 'Sabotage' -

The tracker also showed that the Yi Peng 3 had on Monday been in the area of the C-Lion 1 cable when it was damaged, though there is nothing to indicate that it was involved in the incident.

According to the specialised site VesselFinder, the Yi Peng 3 left the Russian port of Ust-Luga, west of Saint Petersburg, on November 15.

Swedish police also said Wednesday that they were interested in a ship that had been observed in the vicinity of the cables.

They did not specify which ship they were referring to, other than saying it "was currently not in Swedish waters".

Lin Jian, a spokesperson for China's foreign ministry, said Wednesday that he was not aware of the situation but that "China has consistently and fully fulfilled its obligations as a flag state and requires Chinese vessels to strictly abide by the relevant laws and regulations".

On Tuesday, German Defence Minister Boris Pistorius said the severed cables were likely the result of "sabotage".

"Nobody believes that these cables were accidentally severed," he said on the sidelines of a meeting of EU ministers in Brussels.

The prime ministers of Denmark and Sweden echoed that sentiment Wednesday.

"We are closely following what the relevant authorities are saying, and I wouldn't be surprised if it is an external actor that has carried out sabotage," Danish Prime Minister Mette Frederiksen told news agency Ritzau.

- 'Unrest' -

Frederiksen added that given the tensions in the Baltic Sea area there was "a risk of hybrid attacks, cyberattacks and attacks on critical infrastructure".

"We're seeing more and more unrest on several fronts," she said.

Her Swedish counterpart Ulf Kristersson also said the severed cables "very well could be intentional sabotage".

But he cautioned that "this is not something we know yet, I won't speculate on it".

"We live in a time where you need to take every such risk very seriously. We have previously seen sabotage," Kristersson told Swedish news agency TT.

Kremlin spokesman Dmitry Peskov rejected speculations that Russia could somehow be involved.

"It's quite absurd to keep blaming Russia for everything without any grounds. It is laughable in the context of the lack of any reaction to Ukraine's sabotage activities in the Baltic Sea," Peskov said Wednesday.

In October 2023, an undersea gas pipeline between Finland and Estonia had to be shut down after it was damaged by the anchor of a Chinese cargo ship.

And in September 2022, a series of underwater blasts ruptured the Nord Stream pipelines that carried Russian gas to Europe, the cause of which has yet to be determined.

In August, The Wall Street Journal reported that Ukraine's top military commander at the time, Valery Zaluzhny, oversaw a plan to blow up the pipelines, with approval by President Volodymyr Zelensky.

Ukraine rejected the claims as "absolute nonsense".