Poland’s prime minister has raised the country’s security level on energy infrastructure outside its borders, the government's security center said on Oct. 6.

The move comes days after blasts were detected on the Nord Stream pipelines carrying Russian gas across the Baltic Sea to Germany and after the launch of the Baltic Pipe supplying Poland from Norway.

Poland has moved to the second highest of its four-level security preparedness alerts, Bravo, which foresees an increased threat of a terrorist attack on an unspecified target, the security center said.

The new Baltic Pipe which started operating on Oct. 1 crosses Nord Stream pipelines near Bornholm island in the Baltic Sea.

No details were revealed about how the higher alert level will impact security operations. Poland's top energy security official told Reuters last week that measures taken to protect Baltic Pipe were a state secret.

Within Poland, the Bravo level obliges security services to carry firearms and make checks of people, cars and public buildings.

Poland’s energy infrastructure outside the country includes oil refineries in Lithuania and the Czech Republic, controlled by PKN Orlen.

The Baltic Pipe’s operational start launch came one day after ruptures were detected on the Nord Stream pipelines.

Polish Prime Minster Mateusz Morawiecki said those ruptures were an act of sabotage. Read full story

While Polish security services have been monitoring the Baltic Pipe, the project did not formally take on the status of critical infrastructure until it started pumping gas.

“Procedures [aimed at putting the pipeline on the list] are ongoing with the involvement of all relevant services,” Mateusz Berger, the government's representative for Strategic Energy Infrastructure, told Reuters.

A 600-megawatt (MW) Sweden-Poland undersea cable which also crosses the damaged Nord Stream pipelines was intact after the ruptures.

It was halted for maintenance last month and is expected to resume operations this weekend.