Hamas fooled Israel's advanced surveillance by doing all of its planning offline, retired US general says

• Hamas launched a major attack on Israel on Saturday, seemingly catching it off guard.
• A retired US general called it a "classic failure of technology," given Israel's surveillance apparatus.

The latest attack on Israel by the militant group Hamas was a failure of Israel's huge surveillance and defense systems, a retired US general told CNN.

Retired US Air Force Colonel Cedric Leighton called the deadly attacks a ''classic failure of technology," given the strength of Israel's defenses.

Speaking to CNN on Saturday, Leighton highlighted the surveillance techniques that Israel uses in Gaza, including cameras and monitoring radio and telephone communications.

But Leighton said Hamas found ways around those systems.

"What Hamas did, what their leadership did, was apparently they moved off of the normal modern communications links that we take for granted every day, and went back to what you did in the 19th century: face-to-face meetings, they went and used couriers instead of going in and using the telephone or the cell phone," he said.

Israel also uses surveillance drones and an intelligence network in Gaza, and has some of the world's most advanced defense systems, like its Iron Dome anti-missile system.

But Leighton said that Hamas launched missiles with a short, lower trajectory, making them harder for Israel to shoot down.

In a separate CNN interview, Leighton said it doesn't make sense that this attack could happen, given Israel's vast intelligence apparatus.

"I can understand that it would be possible to miss the fact that they are getting together, a specific group at specific a time, and perhaps who those people are, as a specific piece of intelligence," he said.

"But every time there is a meeting of people like Hamas would have had to have had — they would be talking to people, they would be movements in the streets, there would be certain things that would be going on, even if they are not broadcast or not talked about on a cell phone or on a radio or something like that," he added.

Even so, he said it's possible that there was "a failure to connect the dots like we so famously had with 9/11."

Another possible reason, he said, is that Israel likely had a lot of "false alarms" before, and sometimes false alarms "breed a degree of complacency and that complacency, of course, can be fatal, as we're seeing right now."

Another retired US military official, Lt Col. Alexander Vindman, said it was "kind of shocking" that Israel missed the planning of the attacks, while the former head of the Israeli Navy, Eli Maron, called it a "colossal" intelligence failure.

A spokesman for the Israel Defense Forces said Israel was busy fighting, but "I'm sure there will be a lot of discussions about the intelligence down the road."