Ppf query

I have extended my PPF a/c for 5 years in April, 2013. I plan to settle abroad from April, 2014 and will become NRI. 

Now, As per rules, NRI can't open a PPF account, but are allowed to continue existing PPF account till maturity. 

My query is what is the tax implication on the interest earned in the PPF account every year. 

Will I have to infrom the bank about my NRI status .