The head of Israel’s Shin Bet security service has taken responsibility for not warning of the bloody Oct. 7 Hamas rampage that killed over 1,400 Israelis.

In a message sent to Shin Bet workers and their families over the weekend, Ronen Bar wrote that “despite a number of actions we took, unfortunately, on Saturday we were unable to create enough early warning to prevent the attack.”

“As the person at the head of the organization, the responsibility for that is on me,” he added. “There will be time for investigation — now is a time for war.”

The letter was obtained by The Associated Press on Monday.

The Shin Bet leads Israel’s efforts to track and monitor Palestinian militants. The Israeli news site Ynet has reported that on the eve of the attack, Bar was summoned to the office because of abnormal activity detected in Gaza. But officials believed that only a limited attack would take place, according to the report.