If you are still a resident alien, you have to file a U.S. tax return and report your worldwide income, whether or not you live in the United States.
See "Resident Aliens" in IRS Publication 519 for information about how to determine whether you are a resident alien. Download Publication 519 from the following link and see "Resident Aliens" beginning on page 4.
Publication 519, U.S. Tax Guide for Aliens
