Sweden on Tuesday said that a Baltic Sea telecom cable running to Estonia was partially damaged around the same time as a Finnish-Estonian pipeline and cable earlier this month.

Sweden's Civil Defense Minister Carl-Oskar Bohlin said it was unclear what caused the damage to the undersea cable that connects Sweden and Estonia.

"It is not a total cable break. There is a partial damage on this cable," Bohlin said. "We cannot assess what caused the damage. But what we can say is that this damage has happened at a similar time and in physical proximity ... to the damage that was previously reported to a gas pipeline between Estonia and Finland, and a telecommunications cable between Estonia and Finland."

The damage to the cable was sustained outside the territorial waters and Sweden's exclusive economic zone.

Bohlin said that the cable has continued to function since then.

Estonia's economy ministry said the damage to the Swedish-owned cable was in Estonian territory, about 50 kilometers (30 miles) off the island of Hiiumaa, the Baltic News Service reported.

Service was restored within a few days, the agency added.

Sweden, Estonia, and Finland all investigating

On October 8, Finland said that its coast guard had discovered "clear damage" on the Balticconnector natural gas pipeline between Finland and Estonia, which was shut down due to a leak.

The Finnish government later said that it may have been a deliberate act.

On Tuesday, Sweden's Defense Minister Pal Jonson said that his country's police, military and coast guard were in touch with Estonian counterparts on the matter.

He said there also was increased vigilance in the Baltic Sea.

"We see the issue of security for our critical infrastructure as a high priority, and take the current situation seriously," Jonson told reporters.

Europe and NATO are becoming more concerned over the susceptibility of critical infrastructure around and under the Baltic Sea.

Last week, Swedish Prime Minister Ulf Kristersson spoke of a "spaghetti of cables, wires" on the Baltic seabed which "is absolutely fundamental for data traffic."

"We live in a time where civilian infrastructure is also very threatened in this security environment," Kristersson said. "It is also a very clear lesson from Ukraine, i.e., attacking infrastructure that is for energy supply, food supply, water supply."

Both Finland and Sweden have sought to join NATO, having been neutral throughout the Cold War, in the aftermath of Russia's invasion of Ukraine. 

dvv/msh (AP, Reuters)