Israel launched missiles, most likely its Jericho 2 or Jericho 3 ballistic missiles, in a strike against Iran early April 19, ABC News reported, citing a senior U.S. official. Local Iranian media reported that an explosion was heard near the city of Isfahan, which is home to multiple Iranian nuclear facilities and multiple military bases. There are also unconfirmed rumors on social media of explosions inside southern Syria and Iraq, known to be used by the Islamic Revolutionary Guard Corps. It is unclear whether Israel's retaliation to the April 13 Iranian strike on Israel is complete or other sites in Iran have been hit, or whether there will be future waves of attacks. Flights in and out of the Iranian cities of Tehran, Isfahan and Shiraz have been suspended and Tehran has closed airspace across western Iran. Iran has also activated its air defense over several cities, according to state media. 

• The attack comes after Iran's foreign minister told CNN on April 18 that if Israel struck Iran, Tehran would respond at the "immediate and at a maximum level."
• A U.S. official told CNN on April 18 that Israel had informed them that Iran's nuclear program would not be the target of any retaliatory attack, suggesting that the Isfahan targets may have comprised the military bases. 
• Sky News Arabia also reported that Iran's Supreme National Security Council called an emergency meeting for April 19 after the strikes occurred. 

Iran will likely respond to Israel's attack, but the scope and size of Iran's response will depend on the scope of Israel's military actions, which is unclear at this time. A modest Israeli strike on Iran would likely lead to a lower response, but it is possible that Iran still carries out a follow-up strike on Israel. Israeli officials are likely hoping that a narrow strike leads Tehran to try to defuse the situation and only retaliate in a narrow fashion through either a very small attack on Israel or, likely ideal for Israel, only through proxies. Iran's response to the original April 1 Israeli strike on an Iranian consular building in Damascus — which Israeli officials reportedly did not expect would lead to Iranian retaliation striking Iran directly — was much more significant than many people expected, illustrating that there is a high degree of uncertainty regarding Iran's response and the potential of miscalculation, even if the strike is narrow. 

• If Israel's strike proves to be broader, Iran will be in a political position where it will need to respond with more significant action, potentially as large as the April 13 attack involving 300 missiles and drones. Iran may want to try to damage Israeli facilities, which would require Iran to launch hundreds of missiles and drones in an effort to overwhelm the defense capabilities of Israel and its partners.