Israeli officials had intelligence that Palestinian militant group Hamas was preparing a wide-ranging attack before its October 7 assault but dismissed the reports, The New York Times reported Thursday.
The newspaper said a document obtained by Israeli authorities "outlined, point by point, exactly the kind of devastating invasion that led to the deaths of about 1,200 people."
The document, which was reviewed by the newspaper, did not specify when the attack might happen, but provided a blueprint that Hamas appears to have followed: an initial rocket barrage, efforts to knock out surveillance, and waves of gunmen crossing into Israel by land and air.
The Times said the document, which included sensitive security information about Israeli military capacity and locations, circulated widely among the country's military and intelligence leaders, though it was not clear if it was reviewed by senior politicians.
But a military assessment last year determined it was too soon to say the plan had been approved by Hamas, and when an analyst with the country's signals intelligence warned the group had carried out a training exercise in line with the plan, she was dismissed.
She warned it was a "plan designed to start a war," the newspaper said, but a colonel reviewing her assessment suggested: "let's wait patiently."
The warnings did not suggest that Hamas was likely to carry out the plan imminently, and the intelligence community continued to believe that Hamas leader Yahya Sinwar was not pursuing war with Israel, the Times said, likening the intelligence failure to those in the United States before the September 11, 2001 attacks.
The Hamas attack killed 1,200 people, mostly civilians, and saw around 240 people taken hostage, according to Israeli officials.
Israel's retaliatory ground and air offensive in Gaza has killed more than 15,000 people, also mostly civilians, according to Hamas authorities.