The US military carried out a retaliatory strike in Baghdad on Thursday that killed a militia leader it blames for recent attacks on US personnel, a US official told Reuters.
Iraqi police sources and witnesses said a drone fired at least two rockets in eastern Baghdad at a facility used by the Iraqi militia group al-Nujaba'a.
Police and militia sources said the rockets hit a vehicle inside the Nujaba'a headquarters and killed four people, including a local group commander and one of his aides. Health sources confirmed the death toll.
US retaliates Iraqi attacks
The US military has come under attack at least 100 times in Iraq and Syria since the Israel-Hamas war began in October, usually with a mix of rockets and one-way attack drones.
The United States has 2,500 troops deployed in Iraq and 900 in neighboring Syria in a bid to prevent a resurgence of Islamic State militants.
"The Iraqi armed forces hold the international coalition forces responsible for this unjustified attack on an Iraqi security entity," the prime minister's military spokesman said, referring to Thursday's strike.
The statement described the militia group as an Iraqi force operating with the authorization of Prime Minister Mohammed Shia al-Sudani.
The US official said the strike hit the vehicle with the intention of killing the militia leader, and that was accomplished.
Video footage published by pro-militia websites showed a destroyed vehicle in flames. Reuters could not independently verify the authenticity of the footage.
Iran-aligned groups in Iraq and Syria oppose Israel's campaign in Gaza and hold the United States partly responsible.
Iraqi militia threatens to react
Prime Minister Al-Sudani has limited control over some Iran-backed factions, whose support he needed to win power a year ago and who now form a powerful bloc in his governing coalition.
Iraqi security sources said they had no further detail on who might have carried out the strike pending a government investigation.
Iraqi militia commanders accused the United States of carrying out the attack and threatened to retaliate.
"We will retaliate and make the Americans regret carrying out this aggression," Abu Aqeel al-Moussawi, a local Iraqi militia commander, said.
Last month, the United States carried out retaliatory air strikes in Iraq after a drone attack by Iran-aligned militants that left one US service member in critical condition and wounded two others.