The goal of war is to make your enemies surrender and to take their resources. If they are destroying infrastructure then they want control of the land. They can't control the land if it is occupied. Their perceived enemies must flee, surrender or die fighting. They may likely rinse and repeat with Poland, Iceland and then others based on their troop and vessel positioning.
Obligatory, "War never changes." [1] not to belittle a war with a game intro but it holds true
[1] - https://www.youtube.com/watch?v=EM3Y6uw6FtU [video][3 mins]