If PF is withdrawn by an NRI staying in USA does it become taxable as per US laws?

I have been service in an Indian company for 10 years and now getting transferred to US. I want to keep the PF and not withdraw as I don’t need money and it will earn good 8.5% interest for next 3 years. I heard that if I withdraw this money later when I start filling taxes in US all the interest earned on PF (even the interest in previous years and not just these 3 years) will need to be declared as income and would come under tax. Is this true?
My assumption was that only interest earned after I convert to NRI status is the one which becomes taxable. Please clarify.