Israeli Prime Minister Benjamin Netanyahu vowed in early October that his country would retaliate after Iran launched around 180 ballistic missiles toward Israel on October 1, in response to the assassinations of Hamas political leader Ismail Haniyeh in Tehran and Hezbollah leader Hassan Nasrallah in Beirut. However, the timing of the Israeli attack remained unclear.

In a Cabinet meeting on Sunday, ministers were told the attack would be "very soon" and significant, Xinhua news agency reported, citing Israel's state-owned Kan TV.

The report came on Monday hours after US Defence Secretary Lloyd Austin announced the deployment of the Terminal High Altitude Area Defense (THAAD) anti-ballistic missile defence system in Israel in addition to about 100 US soldiers to operate it.

US President Joe Biden had urged Israel to exercise restraint to avoid escalating a broader Middle East conflict, expressing concerns over strikes on Iran's nuclear sites and energy infrastructure.

Iran warned that it would retaliate against any Israeli missile attack.