No group has claimed responsibility for the explosive drone that struck Khor Mor gas field in the Sulaimaniya region of northern Iraq overnight.
It damaged a liquid gas storage tank but caused no injuries, according to the field's United Arab Emirates-based operator, Dana Gas.
Dana Gas said production was temporarily suspended to put out a fire, which was extinguished, and a resumption of operations was expected soon.
Kurdistan's electricity ministry said the attack had led to a 2,800 megawatt drop in power production.
U.S. Ambassador to Iraq Alina Romanowski condemned the attack, saying it "exposed millions to power outages in mid-winter".
Local sources said power from the network had been totally absent in the region since after the attack.
Pearl Petroleum, a consortium of Dana Gas and its affiliate Crescent Petroleum, have the rights to exploit the Khor Mor and Chemchemal fields, two of the biggest gas fields in Iraq.
Iraq has witnessed near-daily drone and rocket attacks since Israel's war in Gaza began in October, mostly targeting bases housing troops belonging to a U.S-led military coalition. They have been claimed by the Islamic Resistance in Iraq, an umbrella group of hardline pro-Iran militias.
In a separate incident on Thursday, an explosive-laden drone targeting U.S. forces at a base near Erbil airport in Iraq's northern Kurdistan region was shot down by air defences, the region's counter-terrorism service said.
(Reporting by Timour Azhari; Writing by Enas Alashray and Timour Azhari; Editing by Rosalba O'Brien and Alison Williams)
