Istanbul | The reimposition of sanctions against Iran on Monday (Tuesday AEDT) has ushered in what is likely to be a protracted period of heated rhetoric and stand-off, as the Trump administration threatened more pressure and Tehran warned that it can ramp up its nuclear program again, Middle East experts said.

In a preview of the war of words that is likely to escalate, Iranian President Hassan Rouhani vowed to continue selling oil in defiance of the sanctions. As state television aired footage of military forces staging war exercises, Mr Rouhani said the country was in an "economic war situation".