The United States had a human intelligence source who confirmed that Ayatollah Ali Khamenei would be holding a meeting at his compound near Pasteur Street in Tehran on Saturday morning, according to two people familiar with the situation cited by the Financial Times. The CIA declined to comment.

As "Hvylya" reports, Israel's intelligence came primarily from signals intelligence - hacked traffic cameras and deeply penetrated mobile phone networks - which showed the meeting with Khamenei was on schedule, with senior officials heading to the location. But the American human source provided an additional, more concrete layer of confirmation.

Israeli military doctrine requires that two separate senior officers, working independently, confirm with high certainty that a target is at the location to be attacked and identify who accompanies him. For a target as high-value as Khamenei, "failure was not an option," the FT reported. The combination of Israeli signals intelligence and the CIA's human asset met that threshold.

Once confirmation came through, Israeli jets - which had already been flying for hours - fired as many as 30 precision munitions at the compound. The Israeli military noted that striking in daylight provided a tactical advantage. "The decision to strike in the morning rather than at night allowed Israel to achieve tactical surprise for the second time, despite heavy Iranian preparedness," it said.

The operation was the product of a joint US-Israeli intelligence effort. While Donald Trump had been publicly building up an "armada" off Iran's shores and grumbling that nuclear negotiations were moving too slowly, a person familiar with the matter said that in private, Trump was "dissatisfied with the Iranian responses" - paving the way for the strike.

Also read: Trump and Israel Launch Major Military Operation Against Iran