A combination of intelligence failure and operational failure on the part of Israel led to the massive death count in the Hamas' attack on Saturday, Israel's former military intelligence head told NDTV in an exclusive interview this afternoon. Major General Amos Yadlin (retired) said the Hamas strike by land, sea and air was a "surprise attack, much like September 11 (9/11), Pearl Harbour". He added that Hamas was a terror organisation like ISIS, only more cruel in its atrocities. "They are killing women, children in a very cold way. Israel won't tolerate that," he said. On the failure of Israel intelligence to pre-empt an attack of this scale, the veteran said this should be investigated at the end of the war. "Signals were not picked up, sensors were neutralised. The consequences were catastrophic," he said.