Are you saying you are a non-resident alien working remotely for an employer? If you have been in the USA long enough to pass substantial presence test then you are a resident for tax purposes and taxed on world income. Therefore you must file form 1040 covering all income no matter where earned.
If you are a non-resident alien then US will tax you ONLY on US connected/ sourced income and you file your return on form 1040_NR which is not supported by TurboTax.
Note that in either case, monies earned while residing in the USA and working remotely for any employer worldwide is treated by the USA as US sourced income and therefore taxed as such . And depending on your status ( non-resident alien or resident for tax purposes), you may be subject to Self-Employment Taxes.
Hope this helps