What's this with "Terrible Tito's terrorists?" If I recall correctly, we helped Tito's resistance fighters, and later the Russians occupied Yugoslavia after pushing out the Germans.
Trieste.
The Russians never occupied Yugoslavia. Tito's government took power as the Germans retreated.
But there was friction along the border between Italy and Yugoslavia, where Yugoslav partisans had "reclaimed" Trieste and the Istrian peninsula from Italy. The area was under dispute until 1948, when Yugoslavia agreed to return Trieste and Italy agreed to let Tito keep Istria.
The U.S. role in this area was "peacekeeping".