Can i use US iTunes account outside US A?

Hi everyone in Y/A community.
Today my relative come from California to visit my family in Thailand.
They also give me an Iphone 5C with an 50$ iTunes giftcard. Which really make me happy. I replace my old iphone 4 with iPhone 5C.
Can I create an US apple Id and use it outside USA?
Can Apple terminated my account even I use legal giftcard?

I live in Thailand and my itunes account is from the USA. So I can't see why not. Just have to list your location as USA.