A series of undersea cables and gas pipelines have been damaged in suspected attacks since Russia’s invasion of Ukraine in 2022, prompting Nato to launch a monitoring mission in the sea last month.

The Swedish coastguard has dispatched a research vessel to the east of Gotland, which is the country’s largest island and the reported location of the latest breach.

Sweden’s Prime Minister Ulf Kristersson has said the government is aware of the cable break and added it “must be seen in the context of the current serious security situation”.

The owner of the cable, Finnish telecom operators Cinia, said it detected minor damage to its fibre-optic cable but added it was still functioning as usual.

Cinia also said it is the third time this cable has been damaged in recent months.

The cable was severed in November last year.

There has been an increase in damage to undersea infrastructure in the Baltic Sea over the past few months, largely caused by civilian ships dragging their anchors across cables.

Swedish police have said “the preliminary investigation relates to suspected sabotage”. The Swedish coastguard has said they do not know when the damage occurred.

“We have a ship called KBV 003 on its way to east of Gotland. It is in the Swedish economic zone and we are assisting with the crime scene investigation,” the coastguard added.

European leaders have suspected Russian involvement in breaches.

However, poor weather, inadequate equipment and human error has been found to be responsible for some damages.

Bulgarian ship the Vezhen was cleared of sabotage by the Swedish authorities earlier this month.

Chinese Ministry of Foreign Affairs spokesperson Mao Ning said at a news briefing in Beijing on Monday that China had invited Germany, Sweden, Finland and Denmark to participate in and complete the inquiry.

Sections of two telecom cables were cut in November in Swedish territorial waters. Suspicions were directed at the Chinese freighter vessel Yi Peng 3, which according to ship tracking sites had sailed over the cables around the time they were cut.

She spoke about the incident when asked about a Financial Times report that Sweden had criticised China for refusing full access despite an open inquiry, and for allegedly barring a Swedish prosecutor from boarding the Yi Peng 3 linked to the cable breach.

Swedish Foreign Minister Maria Malmer Stenergard said China had not heeded the government’s request for the prosecutor to be able to conduct the preliminary investigation on board.

“Our request that Swedish prosecutors together with, among others, the police should be allowed to take certain investigative measures within the framework of the preliminary investigation on board remains,” Stenergard told the Reuters news agency.

“We have been very clear about this with China.”Stenergard said Sweden hoped to continue its dialogue with China with the aim of giving the police and prosecutors the possibility to investigate the cable breaches.

In response, Mao said, “In order to cooperate with the investigation, the Yi Peng 3 was suspended for a long period of time, and to safeguard the physical and mental health of the crew, the shipowner company decided to resume its voyage after a comprehensive assessment and consultation with the parties concerned.”

She added that Beijing had notified all relevant countries in advance and was willing to maintain communication and cooperation.

On Thursday, authorities from Sweden, Germany and Finland were invited on board as observers for an investigation led by China.

A Danish representative also accompanied the group as the country had served a “facilitating role” by hosting meetings between the countries earlier in the week, its Foreign Minister Lars Lokke Rasmussen had said.

Prosecutor Henrik Soderman told the AFP news agency that no measures as part of the Swedish judicial probe had been taken, including questioning crew members or technical investigations.

Following the damage to the Baltic Sea cables, one linking Finland and Germany and the other connecting Sweden to Lithuania, German Defence Minister Boris Pistorius said it was clear to assume this was sabotage.

Investigators zeroed in on the Chinese ship, which had left the Russian port of Ust-Luga on November 15, just two days before the cables were cut on November 17 and 18.

European officials have also stated that they suspect sabotage linked to Russia’s invasion of Ukraine. The Kremlin has rejected the comments as “absurd” and “laughable”.