Israeli Prime Minister Benjamin Netanyahu blocked Gallant from departing to the U.S. on Tuesday night as Israel continued planning its Iran operation, an Israeli official said. U.S. officials said they don’t yet have either the timing of the strike or what Israel might target.

President Biden and Netanyahu are planning to speak on the phone Wednesday, according to an Israeli official.

Last month, Israel carried out a strike against Hezbollah leader Hassan Nasrallah without informing the U.S. ahead of time. The bombing, which took place as Washington was hoping to finalize a cease-fire plan between Israel and Lebanon, surprised senior administration officials.

“Excuse me, what did you say?” Austin said when Gallant told him during a call about the Nasrallah attack, according to U.S. officials familiar with the conversation. During a second call the same day, Austin asked Gallant if Israel was prepared to be “alone” when it came to defending itself, given the lack of notice.

Austin was frustrated because the U.S. didn’t have enough time to position its forces to potentially come to Israel’s defense or to protect nearby U.S. troops, defense officials said.

With Israel promising a response to Iran’s launching of nearly 200 missiles shortly after Nasrallah’s assassination, U.S. officials are hoping this time they will have more insights on a strike that could lead to greater American military involvement.

Israel has at times heeded U.S. advice over the past year. The U.S. sought a more deliberate plan to clear the southern Gaza city of Rafah, which prompted Israel to limit its operations there. The U.S. also persuaded Israel not to launch an attack on Hezbollah in Lebanon based on faulty intelligence just days after Hamas’s Oct. 7 attack.

But Israel’s response to Iran could test the limits of Israel’s responsiveness.