US President Donald Trump said on Monday that he will not rule out boots on the ground in Iran.Trump also told CNN that the “big wave” is yet to come in the war with Iran, adding that Washington does not know who the country’s new leader would be following the killing of Ali Khamenei.“We haven’t even started hitting them hard. The big wave hasn’t even happened. The big one is coming soon,” Trump said, telling CNN it was unclear who was now leading the country.“We don’t know who the leadership is. We don’t know who they’ll pick,” he said.