I can't remember the title of this book!

[Rugwed]

Hi everybody! Need your help in recalling a book's name.I read it quite a while ago and don't remember its name or thr characters in it.I do recall the rough outline.It is set in the period between 1960-1990 (IMO).The story progresses on all three sides:American, British and Russian with three protagonist like characters.In the American narrative,a secret agent gets caught while spying and is imprisoned.(it snows in the where he's caught,Snow camouflage) Maybe the British or the Russians save him. US President and the British PM are about to meet.And the Russian protagonist's two soldiers get shot down in a plane and get a look at their killer before dying.And the climax is that the real villain of the story is the Russian protagonist's godfather....And it has "Falcon" in it,to the best of my memory.