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While nothing is definitive, "all indications are pointing to the fact" that Israel was behind a cyberattack that knocked out power at Iran's Natanz uranium enrichment facility over the weekend, retired U.S. Navy Adm. William McRaven said Monday, and he finds the allegations "a little disturbing" given that the U.S. and other countries are currently trying to renegotiate the 2015 Iran nuclear deal.

"Frankly, I'm not exactly sure what it accomplishes," McRaven told CNN's Jake Tapper. "It's a little bit of a shot across the bow, but Natanz will only be down for maybe a week or so."

McRaven didn't sound too worried about significant retribution from Iran, noting that Tehran doesn't often follow through on its threats, but he expressed concerns about whether this could hamper efforts to strike an agreement on the nuclear pact. However, the blame shouldn't be placed squarely on Israel, McRaven suggested. Tapper asked him if he thought it was plausible that Israel carried out the alleged "act of sabotage without informing the U.S. government, either before or after." That, indeed, "is the problem," McRaven responded. "It implies that [the U.S. was] either complicit or we were ignorant, and neither one of those is a good look for us," he said. Tim O'Donnell