US Defense Secretary Lloyd Austin says it's hard to predict the exact nature of an Israeli strike on Iran and how Tehran will respond. Austin emphasizes that it is ultimately an Israeli decision and that perceptions of proportionality may differ between the two countries. He expresses the US's commitment to de-escalating tensions and hopes for both parties to engage in de-escalation. Austin also confirms the presence of a US missile defense system in Israel. Iran has been anticipating retaliation following its attack on Israel on October 1, which was in response to Israeli strikes in Lebanon and a blast in Tehran.