"An operation was planned for the middle of the year with the same target set," Katz said in an address to military intelligence officials, according to a statement issued by his office.

"But due to developments and circumstances -- mainly what happened inside Iran, the position of the US president and the possibility of creating a combined operation -- it became necessary to move everything up to February."

During mass anti-government protests in Iran in January, which were suppressed in a violent crackdown by security forces, Trump pledged support for demonstrators, declaring that the United States stood with the people of Iran.

Top Israeli officials, including Prime Minister Benjamin Netanyahu, made similar remarks, urging Iranians to rise up against the country's clerical leadership.

The United States and Israel jointly launched strikes on Iran on Saturday, and in the initial wave of attacks, they killed the Islamic republic's supreme leader Ayatollah Ali Khamenei.

Iran retaliated swiftly with missile fire targeting Israel and also launched strikes against several countries in the region, saying it was aiming at US assets.

Iran's official IRNA news agency said Wednesday that US-Israeli strikes had killed 1,045 military personnel and civilians since the start of the war. AFP was not in a position to independently verify the toll.

Iranian strikes on Israel have killed 10 people and injured scores more, according to Israeli authorities.