The Biden administration notified Israel in advance about the airstrike against an Iranian-backed Shiite militia base on the Syrian-Iraqi border Thursday evening, Israeli officials told me.

Why it matters: The airstrike was the first overt military action by the U.S. in the Middle East since Biden assumed office, and one that Israeli officials see as a positive signal about the new administration's posture toward Iran.

Driving the news: The U.S. notification to Israel took place Thursday morning ET in talks between working-level officials at the Pentagon and the Israeli Ministry of Defense.

• Israeli officials told me it was a standard update that occurs every time a U.S. military operation can influence Israel and vice versa.

Behind the scenes: The strike came several weeks after a missile attack on a U.S. base in Erbil in northern Iraq. The U.S. retaliation was delayed mainly in order to coordinate it with the Iraqi government and avoid creating a crisis with Iraq.

• In recent weeks, Israeli officials were concerned by growing provocations by Iran and its proxies both in Yemen and in Iraq.
• The Israelis shared their concerns with the Biden administration. Israeli officials told me they expected that Biden would respond.

What they're saying:"The Iranians didn’t realize that Biden is not Obama, and that if they will continue down this road of miscalculation they will eventually get hit," an Israeli official told me.

Between the lines: A year ago, a group of experts from the Center for New American Security led by former Obama administration official Ilan Goldenberg published a paper called "Countering Iran in the Gray Zone."

• They spoke to numerous Israeli defense officials to determine what the U.S. can learn from the Israeli military campaign against Iranian entrenchment in Syria, which the Israelis call the "Campaign Between Wars," or MABAM in Hebrew.
• The bottom line of the report was that the U.S. should examine whether it could adopt this Israeli policy. It stressed that targeted strikes against Iran or other adversaries in the Middle East would not definitely lead to a wide escalation, as many in the U.S. defense establishment fear.

What’s next: It's unclear if the strike was a one-off event or whether it will turn into a doctrine, but it's an attempt by Biden to send Iran an early message that he is not afraid to use force to retaliate against attacks on U.S. forces in the region. It also indicates his wish to return to the 2015 nuclear deal will not deter him from using military force when needed.