The social media post went up online at 1:10 a.m. Sunday, while most Israelis were sleeping.

Prime Minister Benjamin Netanyahu had a message: His military and security chiefs, he said, had failed to provide him with any warning of the surprise Hamas assault on Oct. 7. He appeared to be placing all the blame on them for the colossal lapses — even as Israeli forces were broadening a risky ground war in Gaza.

The country awoke to a furious response, including from within Mr. Netanyahu’s own war cabinet. The post on X, formerly Twitter, was deleted, and the Israeli leader apologized in a new one. “I was wrong,” he said.

But the damage was done.

For many Israelis, the episode confirmed suspicions of rifts and disarray at the top during one of the worst crises in the country’s 75-year history and reinforced qualms about Mr. Netanyahu’s leadership.

“He’s in survival mode,” said Gadi Wolfsfeld, an expert in political communications at Reichman University in Herzliya, north of Tel Aviv.

“He’s been in difficult circumstances before, and he still believes he can come out of this and continue to be prime minister when this is all done,” Professor Wolfsfeld said, adding, “The only thing driving him is staying in power.”

Among the first to call out Mr. Netanyahu’s middle-of-the night comments was Benny Gantz, the centrist former defense minister and military chief who, for the sake of national unity, left the ranks of the parliamentary opposition to join Mr. Netanyahu’s emergency war cabinet in the days after the massacre by Hamas. At least 1,400 people were killed in those attacks — it was the deadliest day for the Jewish people since the Holocaust — and at least 239 were taken as hostages to Gaza.