https://www.independent.co.uk/news/world/europe/nato-jets-in...
Also with cables, they can be destroyed with "innocent" ships that have a right to be there actually :)
https://www.bbc.com/news/world-europe-65309687
Russia has a programme to sabotage wind farms and communication cables in the North Sea, according to new allegations.
The details come from a joint investigation by public broadcasters in Denmark, Norway, Sweden and Finland.
It says Russia has a fleet of vessels disguised as fishing trawlers and research vessels in the North Sea.