I have a client who moved to US about 3 years ago from Turkey. In 2018, he received bulk sum amount of his retirement from Turkey government.

Does this amount need to be reported, and where on 1040 form? Is the amount taxable (notice: retirement amount is the result of the client's previous employment in Turkey, before becoming US resident)?

If taxable, can the amount be excluded under tax treaty as  Turkey and US has one?

* I am trying to report the amount, but exclude it from taxation

Thanks.