A rocket hit a site in southern Iraq used by foreign oil companies on Wednesday, including U.S. energy giant ExxonMobil, wounding three people and threatening to further escalate U.S.-Iran tensions in the region.
There was no immediate claim of responsibility for the attack near Iraq's southern city of Basra, the fourth time in a week that rockets have struck near U.S. installations.
Three previous attacks on or near military bases housing U.S. forces near Baghdad and Mosul caused no casualties or major damage. None of those incidents were claimed.
An Iraqi security source said it appeared that Iran-backed groups were behind the Basra incident.
"According to our sources, the team (that launched the rocket) is made up of more than one group and were well trained in missile launching," the security source said.
He said they had received a tip-off several days ago that the U.S. consulate in Basra might be targeted but were taken by surprise when the rocket hit the oil site.
Hostility between the United States and Iran has been rising since President Donald Trump withdrew the United States from a 2015 nuclear deal with Iran and other world powers in May last year.
Trump has since reimposed and extended U.S. sanctions on Iran, forcing states to boycott Iranian oil or face sanctions of their own. Tehran has threatened to abandon the nuclear pact unless other signatories act to rein in the United States.
The U.S. face-off with Iran has reached a new pitch following attacks on oil tankers in the Gulf in May and June that Washington blames on Tehran. Iran denies any involvement.
Iraqi officials fear that their country, where powerful Iran-backed Shia Muslim militias operate in close proximity to some 5,200 U.S. troops, will become an arena for any violent escalation.
The United States has pressed Iraq's government to rein in Iran-backed paramilitary groups.
Oil exports unaffected
Iraq's military said three people were wounded in Wednesday's strike by a short-range Katyusha missile. It struck the Burjesia site, west of Basra, which is near the Zubair oilfield operated Italy's Eni SpA.
Police said the rocket landed 100 metres from the part of the site used as a residence and operations centre by Exxon. Some 21 Exxon staff were evacuated by plane to Dubai, a security source said.
Exxon had evacuated its staff from Basra after a partial U.S. Baghdad embassy evacuation in May and Exxon's staff had just begun to return.
Burjesia is also used as a residential and operations headquarters by Royal Dutch Shell PLC and Eni., according to Iraqi oil officials.
The oil officials said operations including exports from southern Iraq were not affected by the incident.
A separate Iraqi oil official who oversees foreign operations in the south said the other foreign oil firms had no plans to evacuate and would operate as normal.
A spokesman for Shell said its employees had "not been subject to the attack ... and we continue normal operations in Iraq."
Spate of incidents
Wednesday's rocket strike fits into a pattern of attacks since May, when four tankers in the Gulf and two Saudi oil pumping stations were attacked.
They have been accompanied by a spate of incidents inside Shia-dominated Iraq, which is allied both to the United States and fellow Shia Muslim Iran.
The attacks in Iraq have caused less damage but have all taken place near U.S. military, diplomatic or civilian installations, raising suspicions they were part of a concerted campaign.
A rocket landed near the U.S. embassy in Baghdad last month causing no damage or casualties. The United States had already evacuated hundreds of diplomatic staff from the embassy, citing unspecified threats from Iran against U.S. interests in Iraq.
Iran backs a number of Iraqi Shia militias which have grown more powerful after helping defeat Islamic State.
Iraqi officials say that threats from Iran cited by Washington when it sent additional forces to the Middle East last month included the positioning by Iran-backed militias of rockets near U.S. forces.
Rockets hit on or near three separate military bases housing U.S. forces near Baghdad and in the northern city of Mosul in three separate attacks since Friday.
*This story was edited by Ahram Online