Are you US citizen/resident ( Green Card )? if so you are taxed on world income and therefore it is taxable income to the USA. However, once you have established a tax home in a foreign country ( meet the substantial presence test ), you may be eligible to exclude most ( if not all ) of foreign eanred income from US taxes .
Please provide answers to q's above and also when did you leave USA, are you working for US entity or a local entity? Is your family with you ?