The US is "outraged" by a deadly rocket attack on Monday that occurred near the Irbil International Airport in the Iraqi Kurdistan region, US Secretary of State Antony Blinken said.
At least one person was killed and several others were injured, including an American service member and several American contractors, Blinken said.
"We express our condolences to the loved ones of the civilian contractor killed in this attack, and to the innocent Iraqi people and their families who are suffering these ruthless acts of violence," he said in a statement.
At least three rockets hit areas between the airport in the semi-autonomous Kurdish-run region and the nearby base hosting US troops at around 9:30pm local time on Monday evening.
A spokesperson for the US-led coalition said the person killed was a civilian contractor but did not reveal the nationality of the contractor.
A statement from Kurdistan's Interior Ministry said "several people" had been injured based on a preliminary investigation.
Iraqi President Barham Salih said in a statement that the attack marked a "dangerous escalation" and was "a criminal terrorist act targeting national efforts to protect the security of the country and the safety of citizens".
"We have no choice but to firmly strengthen our efforts to root out the forces of terror and the attempts to plunge the country into chaos".
Masrour Barzani, prime minister of the Kurdistan Region of Iraq, said he condemned "in the strongest terms tonight’s rocket attacks on Erbil. I urge all Kurdistanis to remain calm".
He said he had instructed security services to begin a full investigation into the attack.
Kurdish authorities cautioned Irbil residents to stay away from targeted areas and remain in their homes.
Although no one immediately claimed responsibility for the attack, a little-known Shiite militant group later claimed responsibility.
"The American occupation will not be safe from our strikes in any inch of the homeland, even in Kurdistan, where we promise we will carry out other qualitative operations," the claim said, according to the SITE Intelligence Group.
Attacks targeting Irbil airport are rare, with Monday's rockets the first to strike the area in five months.
Rocket attacks have frequently targeted the US presence in Baghdad, including the US Embassy, as well as convoys ferrying materials for the US-led coalition.
Former US President Donald Trump had said the death of a US contractor would be a red line and provoke US escalation in Iraq. The December 2019 killing of a US civilian contractor in a rocket attack in Kirkuk sparked a tit-for-tat fight on Iraqi soil that brought the country to the brink of a proxy war.
US forces have been significantly reduced in Iraq to 2,500 personnel and no longer partake in combat missions with Iraqi forces in ongoing operations against the Islamic State group.