filming location and plot location

I'm guessing it was filmed in Vancouver but is the plot supposed to be set in Canada or the US. When the girl is in the park with the old man the Cop is clearly Canadian although I couldn't get a good look at his uniform to know what city he's supposed to be in. When the girl is watching the TV though it shows the city of Dallas or at least a significant portion of Dallas being totally destroyed which appears to be triggering a US government response. I'm from the U.S. and I just assumed this was taking place in the U.S. Does this film take place in the U.S. or Canada or was the film clever enough to make that ambiguous.