NATO and its eight Baltic Sea allies say they are stepping up efforts to deter 'any attempts at sabotage' in the wake of a series of incidents that have damaged key undersea power and telecommunications cables.

Crew on board an oil tanker accused of sabotaging undersea power and communications cables in the Baltic Sea were poised to cut other cables and pipelines when Finnish authorities boarded the vessel last month,

"Had it continued for another 12 minutes, the carnage would have been much worse than the four basic cables that were there," Finnish President Alexander Stubb said.