DOHUK, Iraq -- A barrage of rockets was fired Wednesday at the Ain al-Asad air base in Iraq's western Anbar province -- one of the last remaining Iraqi bases where American forces are stationed.
An Iraqi security statement and one released by the Pentagon said 10 rockets were launched toward the sprawling base.
A senior Defense Department official said a U.S. contractor died of an apparent heart attack during the rocket barrage. Officials in Washington did not identify the group responsible for the attack.
The Pentagon said in a statement that the missile defense system at al-Asad "engaged in defense of our forces" and added, "We extend our deepest condolences to the loved ones of the individual who died."
President Joe Biden was briefed on the attacks, press secretary Jen Psaki told reporters at the White House on Wednesday.
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Psaki said officials were leaving their options open, pending an investigation of the incident, but she acknowledged a caution against making "a hasty or ill-informed decision" that "plays into the hands of our adversaries."
The Sabareen news outlet, which is affiliated with Iran-backed militias, said three U.S. soldiers had been killed in the attack -- a report completely at odds with the official Defense Department account.
The assault took place less than a week after the United States attacked Iran-backed militia targets at the Syria-Iraq border. Those airstrikes, ordered by the Biden administration, hit a collection of buildings on the Syrian side of a border crossing. Biden had originally approved two targets inside Syria, administration officials said.
The Iran-backed militia Kata'ib Hezbollah said one of its fighters had been killed in those airstrikes. It identified him as a member of Popular Mobilization Forces that are officially part of Iraqi security forces helping prevent infiltration by the Islamic State.
The second strike Biden approved was aborted after American forces learned that there were women and children at that site, also in Syria, administration officials said. Two F-15E Strike Eagles dropped seven 500-pound satellite-guided bombs on nine buildings at Abu Kamal, the first site, the officials said.
Biden chose targets in Syria to avoid political blowback on the Iraqi government, officials said.
The assault on the base Wednesday occurred just days before a visit by Pope Francis to Iraq -- the first papal visit to the war-ravaged country.
Iraqi security forces are on heightened alert, with Baghdad going into full lockdown Friday. Security forces have been deployed in large numbers to all of the cities Francis plans to visit on his three-day trip.
The attackers who targeted the base Wednesday used BM-21 "Grad" rockets, fired about 5 miles from the base, officials said.
A paramilitary leader near the base said he had heard the impact of the rockets and then went to investigate. The leader, Sheikh Qutri Kahlan al-Obeidi, said he had found "a burned vehicle -- a Mitsubishi pickup" rigged with rocket launchers that appeared to have been used in the attack.
No group took responsibility, but any additional deaths will add pressure to the Biden administration to respond, even as the pope's visit could complicate any immediate military escalation.