U.S. officials said the airstrike happened in Musayib, a town south of Baghdad, but disclosed few other details. A defense official said in a brief statement that “based on recent attacks in Iraq and Syria,” U.S. military officials assessed that the activity constituted a threat to American and coalition forces. Like some others, this official spoke on the condition of anonymity to discuss the operation.

“This action underscores the United States’ commitment to the safety and security of our personnel,” the statement said. “We maintain the inherent right to self-defense and will not hesitate to take appropriate action.”

A second defense official said the airstrike followed three attacks on U.S. forces in recent days. On Thursday, two rockets targeted al-Asad Air Base in Iraq and another struck on or near a U.S. outpost in Syria, the official said. The following day, two additional rockets targeted the facility in Syria, Mission Support Site Euphrates. No damage or injuries were reported in any of those incidents, the official said.

U.S. officials have long feared that Israel’s war in Gaza could spill over into other parts of the Middle East, where Iran enjoys considerable influence.

Tuesday’s airstrike, reported earlier by Reuters, follows a spike in violence between Israel and Hezbollah, a powerful Iranian-backed group in Lebanon.

Earlier in the day, Israel carried out an airstrike in a busy neighborhood on the outskirts of Beirut, saying it had killed a senior Hezbollah commander responsible for an attack Saturday that killed 12 children in the Israeli-controlled Golan Heights. The Lebanese Health Ministry said the attack killed a woman and two children. Hezbollah denied it was responsible for the weekend attack.

Defense Secretary Lloyd Austin, speaking to reporters after meeting with officials in the Philippines on Tuesday, expressed hope for a diplomatic resolution to avoid a full-blown conflict but said the United States will defend Israel if it is attacked by Hezbollah. “We’ve been clear about that,” he said.

In the weeks after Hamas-led militants launched a deadly cross-border attack into Israel on Oct. 7, spawning the ongoing war in Gaza, other militant groups backed by Iran started attacking U.S. military positions in Iraq, Syria and Jordan, linking their violence to Washington’s support for Israel. The militias in Iraq and Syria, along with the Houthis in Yemen, Hezbollah in Lebanon, and Hamas in Gaza, are all part of the same network and are provided weapons and training by Iran, U.S. officials have said.

In February, after at least 165 attacks on U.S. forces, the Biden administration approved airstrikes in response to, and to avenge, the deaths of three U.S. soldiers killed in a one-way drone strike on their base in Jordan.

Tuesday’s airstrike in Iraq occurred as U.S. and Iraqi officials negotiate a possible withdrawal of at least some of the approximately 2,500 U.S. troops in Iraq. An additional 900 troops are based in Syria, with a mission to counter the Islamic State, and are reliant on personnel in Iraq for logistical help.