<sod >Â  A source of disagreement was the Iran nuclear deal, the Obama-era agreement in whichÂ Iran agreed to restrict its nuclear programme for at least 10 years in exchange for the loosening of economic sanctions.< eod>< sod > In the speech about his departure he did not thank Mr Trump once, but praised the "honesty" and "respect" shown by his State Department staff A source of disagreement between Mr Trump and Mr TillersonÂ was the Iran nuclear deal, the Obama-era agreement in whichÂ Iran agreed to restrict its nuclear programme for at least 10 years in exchange for the loosening of economic sanctions.< eod>