Multiple US officials across the region and in Washington told CNN that the US expects Iran to retaliate in the coming days – perhaps even within the next 24 hours – against Israel for Ismail Haniyeh’s killing.

But the US has struggled to gauge when the response will come and what form it will take, in part because Iran already moved some of the military assets necessary to carry out a major attack on Israel in April, making it more difficult for US intelligence to predict its actions now.