Most major countries have been doing this for years and years.
The US used to tap undersea cables way back around the 1970s. (Book: "Blind Man's Bluff")
Great Britain cut the undersea cables between Germany and the US way back in World War One, so that the Germans would be forced to use radio (which could be intercepted and decoded) instead of their undersea telephone cables.
Most major countries have been doing this for years and years.
The US used to tap undersea cables way back around the 1970s. (Book: "Blind Man's Bluff")
Great Britain cut the undersea cables between Germany and the US way back in World War One, so that the Germans would be forced to use radio (which could be intercepted and decoded) instead of their undersea telephone cables.