Not when it is your own territorial waters.
I do agree that blockade is an act of war, but they’re already in state of war that is started by the other side. If the other side keep sending terrorist over their territory your country without doing anything to stop it, then under international law, Israel HAVE the right to cross over that border to stop it
If we used US territorial waters and territory to stop trade between the Navajo nation and the rest of the world, I think the Navajo might consider it an act of war.