BAGHDAD, Iraq — Iraq’s electricity system suffered a major blow on Tuesday after Iran halted gas supplies, the country’s electricity ministry said. The stoppage, which led to the loss of 4,000 to 4,500 megawatts of power, affected multiple generating units and forced load shedding across the country.

“The Iranian side sent a telegram informing the Ministry of Electricity of the complete cessation of gas supplies due to unforeseen circumstances,” the ministry said in a statement. Iran provides between a third and 40% of Iraq’s gas and electricity needs.

The disruption comes after the U.S. administration of former President Donald Trump rescinded a waiver in March that had allowed Iraq to pay Iran for electricity, part of Washington’s “maximum pressure” campaign against Tehran, further complicating Iraq’s chronic power shortages.