U.S. officials say Israel has narrowed down its targets for strike on Iran

U.S. officials believe Israel has narrowed down what they will target in their response to Iran's attack, which these officials describe as Iranian military and energy infrastructure.

There is no indication that Israel will target nuclear facilities or carry out assassinations, but U.S. officials stressed that the Israelis have not made a final decision about how and when to act.

The region has been on edge awaiting Isreal's response to an Iranian missile barrage launched on Oct. 1, which Iran said was in response to Israel's invasion of Lebanon and the assasination of its allies, including Hamas' Ismail Haniyeh in Tehran, and Hezbollah's powerful leader, Hassan Nasrallah in Beirut.

Iran's attack caused little damage in Israel.

The U.S. does not know when Israel's response could come but officials said the Israeli military is poised and ready to go at any time once the order is given.

U.S. officials stressed that they have no information to indicate the response will come today but admitted that Israel has not shared a specific timeline with them — and it is not clear Israeli officials have even agreed on one yet.

U.S. and Israeli officials said a response could come during the Yom Kippur holiday. 

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Israel has shared more information with the U.S. about the retaliation, the officials said, but they withheld many details out of operational security concerns. The U.S. is poised to defend its assets in the region from any immediate counterattack from Iran but is not