U.S. fighter jets conducted “a self-defense strike” at a weapons storage facility in Syria that was being used by Iran’s Islamic Revolutionary Guard Corps, Defense Secretary Lloyd Austin said Wednesday.

The strike in eastern Syria was carried out at President Joe Biden’s direction, Austin said in a statement.

“This precision self-defense strike is a response to a series of attacks against U.S. personnel in Iraq and Syria by IRGC-Quds Force affiliates,” Austin said.

It’s the second time in recent weeks that the U.S. has attacked targets in Syria.

In late October, the U.S. launched strikes against Iran-linked targets in Syria as a response to attacks by Iranian-backed militia groups against U.S. personnel in Iraq and Syria, Austin said at the time.

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Forty-six U.S. service members have been injured, some with traumatic brain injuries, in recent attacks in Iraq and Syria, the Department of Defense said.

Since Oct. 17, U.S. and coalition forces have been attacked at least 40 times — 22 times in Iraq and 18 times in Syria by a mix of one-way attack drones and rockets, defense officials said.

Biden “directed today’s action to make clear that the United States will defend itself, its personnel, and its interests,” Austin said in Wednesday’s statement.

“The U.S. is fully prepared to take further necessary measures to protect our people and our facilities. We urge against any escalation,” Austin said.