U.S. intelligence says "catastrophic motor failure" of rocket launched by Palestinian militants caused hospital blast

U.S. intelligence officials said Tuesday that they used signals intercepts, multiple video sources, photographs and geolocation technologies to arrive at a "high confidence" assessment that Israeli munitions were not the source of the deadly blast at Gaza's Al-Ahli hospital last week, laying out new details about an incident that has inflamed tensions across the Middle East.  

Instead, officials said, the explosion was likely caused by a rocket launched by Palestinian militants that suffered from "catastrophic motor failure," which split off and then propelled the weapon's warhead into the hospital compound.

Analysts concluded with low confidence, based on signals intercepts, that the Palestine Islamic Jihad extremist group was responsible for the launch. The officials who described the analysis spoke on a condition of anonymity to describe sensitive information. 

The intercepts involved Hamas militants speculating about who had launched the weapon, officials said.

"We can't confirm who they are. We can't confirm that what they are discussing in the intercept actually took place," an American intelligence official said.   

The officials detailed two reasons for their more conclusive judgment that Israeli forces were not responsible for the Oct. 17 explosion. First, they said, the light structural damage caused to the hospital was consistent with a rocket and "inconsistent with the larger craters and broader blast effects" that are associated with air-dropped munitions or artillery rounds.  

Secondly, they said multiple flight videos of the launch indicated that the rocket was launched from within the Gaza strip and traveled northeast. Within seconds of its launch, officials said the "fluctuating intensity" of the rocket's plume suggested an unstable motor combustion, which was followed by one object hitting the ground, and was soon followed by a second.  

"Our conclusion is that there was a catastrophic motor failure that likely occurred, which separated the motor and the warhead," one of the officials said. "The warhead landed in the hospital compound, and that was the second explosion, and a much bigger one."   

There was no update to an initial, low-confidence assessment by U.S. agencies that the blast resulted in 100 to 300 casualties, a count lower than what Hamas has claimed.

"It's very hard to get a good sense for what went on, especially with the fog of war," one official said.

The officials said the failure rate for domestically produced rockets in Gaza was "pretty high."  

"[T]his does fit within a longstanding, years-long pattern, in terms of rocket performance," one official added. There was "no indication" that the hospital was an intended target of the militants, he said.  

The officials said intelligence analysts had reviewed open-source images and videos of any debris from the blast that could have come from Israeli munitions, as Palestinian forces have claimed, but had found no supporting evidence. They also said analysts had ruled out that any kind of Iron Dome interceptor caused the breakup.  

"We are confident that the video that we analyzed shows a rocket coming out of Gaza, suffering a catastrophic failure and then landing back in Gaza, not having been intercepted by Iron Dome," one official said.   

The officials said the intelligence community could not rule out that new information could come to light to change their assessment. 

A senior intelligence official who took part in Tuesday's briefing also said that intelligence agencies' independent visibility into extremist activities in Gaza was "limited."  

"Over time, what we've relied on is increasingly our Israeli partners to share with us insight into what's going on," he said.   

In:
• Hamas
• Israel
• Gaza Strip
• Missile Launch