A drone attack halted production at an oil field run by the U.S. company in Iraq's semi-autonomous northern region on Tuesday after two drones caused material damage at another field near Irbil overnight.
Production was halted as a precautionary measure after an explosion at the Sarsang field, two engineers told Reuters, while Iraqi Kurdistan's ministry of natural resources said the blast was from a drone attack.
Iraq's Kurdistan Regional Government (KRG) said the Sarsang oil field in Duhok province was hit, calling the strike "an act of terrorism against the Kurdistan Region's vital economic infrastructure."
No group has claimed responsibility for the attack, but regional security sources told Reuters that initial investigations suggested that the drone came from areas under the control of Iran-backed militias.
The attack followed a similar drone strike a day earlier on an airport in neighboring Irbil province, which hosts U.S. troops.
HKN Energy, the U.S. firm operating the site, said the blast occurred at about 7 a.m. (4 a.m. GMT) at one of its production facilities in the Sarsang field.
"Operations at the affected facility have been suspended until the site is secured," it said in a statement.
Heavy plumes of smoke were seen rising from the Sarsang field, said one oil engineer at the field.
There were no casualties, the ministry and HKN Energy said.
The incident is under investigation and a full assessment of the damage has been initiated, the company said without providing further details on the cause of the explosion.
In the past few weeks, Iraq, particularly its northern region, has seen a spate of unclaimed drone and rocket attacks.
Long plagued by conflict, Iraq frequently experiences such attacks, often linked to regional proxy struggles between Iran and the U.S. and its ally, Israel.
The explosion in the Sarsang field occurred a day after three explosive-laden drone attacks were reported in KRG. Apart from a drone shot down near Irbil airport, which hosts U.S. troops, another two hit the Khurmala oil field, causing material damage, a report by Agence France-Presse (AFP) said.
There has been no claim of responsibility for those attacks.
But, on July 3, the Kurdistan authorities said a drone was downed near Irbil airport, blaming the Hashed al-Shaabi, a coalition of pro-Iran former paramilitaries now integrated into the regular armed forces.
The federal government in Baghdad rejected the accusation.
The latest attacks occur at a time of heightened tension between Baghdad and Irbil, the seat of the regional government, over oil exports. A major pipeline through Türkiye has been shut since 2023 due to legal disputes and technical issues.
In May, Iraq's federal authorities filed a complaint against the autonomous Kurdistan region for signing gas contracts with two U.S. companies, including HKN Energy.
Iraq slammed the agreements, stating that all oil and gas development must be approved by the federal government.
A few hours after Tuesday's drone attack, Iraq's oil ministry announced an initial agreement with HKN Energy to develop the Hamrin oil field in Salaheddin province.
After signing the agreement, Iraqi Oil Minister Hayan Abdel Ghani said Baghdad is looking forward to cooperating with U.S. companies in the oil and gas fields.
'Unacceptable'
The U.S. Embassy in Baghdad denounced "the recent drone attacks throughout Iraq," including strikes on "critical infrastructure" at oil fields in Kurdistan.
"These attacks are unacceptable," the Embassy said on social media platform X, urging Baghdad to investigate.
The Iraqi government "must exercise its authority to prevent armed actors from launching these attacks against sites ... including locations where Iraqi and international companies have invested in Iraq's future," it added.
There are some 2,500 U.S. troops in Iraq as part of the international coalition against Daesh.