Drone attacks on Saudi Arabia’s oil industry in May may have been carried out from Iraqi territory, not Yemen by Houthi rebels as previously thought, US officials have reportedly concluded. Iraqi Prime Minister Adel Abdul Mahdi last week denied the attacks could have come from Iraqi territory but US officials familiar with the investigation told the Wall Street Journal that Iranian-backed militias in Iraq were the most likely culprits. On May 14, Saudi Arabia's Minister of Energy, Industry and Mineral Resources <a href="https://www.thenational.ae/world/gcc/saudi-arabia-s-oil-infrastructure-attacked-by-drones-energy-minister-khalid-al-falih-says-1.861314">Khalid Al Falih said that two oil-pumping stations for the vital East-West pipeline had been hit by explosive-laden drones</a>. He called the attack "an act of terrorism" that targeted global oil supplies. Officials from the Arab coalition to support the internationally recognised government of Yemen against the rebels blamed the Houthis, who have fired hundreds of missiles, drones and other projectiles over the kingdom’s southern border in recent years. In other, unconnected, attacks last month, the rebels fired a missile at Abha airport that wounded over 20 civilians. The State Department declined to comment on the report. The WSJ report said that US experts believed that the technology used in the pipeline attack was much more sophisticated than the Houthis are believed to have in their arsenal. The pipeline, that bisects the country north of the capital of Riyadh, is closer to the Iraqi border than the Yemeni frontier and does not have the same build-up of missile defence systems as areas closer to the southern front. The WSJ report quoted US officials expressing concern that a second front had opened up against the kingdom. US officials have urged the government in Baghdad to prevent the country being used to stage attacks against US assets or its allies in the region given the abundance of Iran-backed militias that operate with significant political cover as many have MPs in parliament. Iraqi officials have also ordered the militias not to use the country to wage proxy wars. During the battle against ISIS after 2014, the Iraqi government allowed largely Shiite militias to join the security services protecting the capital and then battling the extremists. The militia members are paid a government salary and the forces are now recognised as a component of the national security forces despite having their own leadership structures and autonomy. The pipeline attack took place two days after four vessels, including two Saudi oil tankers, were damaged by sabotage off the coast of the United Arab Emirates. Iraqi militias have also been blamed for a string of rocket attacks in Iraqi in recent weeks. One hit a compound used as headquarters by major oil companies, including US giant Exxon Mobil, wounding several civilians in the southern city of Basra and others have hit military bases housing US troops. One landed less than a kilometre from the US embassy in Baghdad. In his denial, Mr Abdul Mahdi said they had no intelligence to suggest the attacks originated in southern Iraq. "All of our intelligence services and our air force denied these reports because the air space is known," Mr Abdel Mahdi said. "As far as we are concerned, we have no proof and we have no evidence in this matter." He said none of the Iraqi intelligence or military services that monitor its air space detected any launch. "There was no movement on that day on this subject," he said.