Several undersea telecom and power cables have been damaged in the Baltic Sea in recent months, with observers accusing Moscow of orchestrating a hybrid war against Western countries supporting Ukraine.

Before the EU's announcement, Sweden said Friday it was investigating suspected damage to an underwater cable east of the Baltic island of Gotland.

The European Commission said it would step up security requirements for underwater cables and prioritise financing for the deployment of new and smart cables.

It also said the EU would increase the capacity for the swift repair of damaged cables and would enforce sanctions against "hostile actors" and the "shadow fleet".

Security analysts say Russia is operating a "shadow fleet" of hundreds of vessels, aiming to dodge Western sanctions -- some of whom are accused of damaging cables.

"Today we are taking steps to protect cables, detect and anticipate threats more quickly, and repair damage as fast as possible," top EU diplomat Kaja Kallas said.

"Anyone found to be responsible for sabotage should be punished accordingly -- including with sanctions. Would-be perpetrators must also be deterred," Kallas said in a statement.

Brussels said it will roll out concrete actions later this year and the next.

The bloc will work with private firms to report incidents quicker, an EU official said, noting some 60 percent of fibre optic cables are operated by private companies.

The EU made no mention of Russia in its statement but there have been heightened tensions between Moscow and the West since the Kremlin's 2022 invasion of Ukraine.

The first major incident came in September 2022 when a series of underwater blasts ruptured the Nord Stream pipelines that carried Russian gas to Europe.

There have since been more in 2023 and 2024 including on December 25 last year when the Estlink 2 electricity cable and four telecom cables linking Finland and Estonia were damaged.