Three people were injured on Wednesday when a rocket struck a residential and operations headquarters of several global major oil companies, including US giant ExxonMobil, near Iraq’s southern city of Basra.
There was no immediate claim of responsibility for the attack, the fourth time in a week that rockets have struck near US installations.
Three previous attacks on or near military bases housing US 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 in southern Iraq 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, according to Reuters.
He said they had received a tip-off several days ago the US consulate in Basra might be targeted but were taken by surprise when the rocket hit the oil site.
Iranian officials have made no comment about the attack but have strongly denied all other allegations against them of attacking energy tankers and facilities in the region.
US-Iranian hostility has risen since President Donald Trump withdrew Washington from a 2015 nuclear deal with Iran and other world powers in May last year.
Trump has since reimposed and extended US 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 US face-off with Iran 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.
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 meters from the part of the site used as a residence and operations center by Exxon. Some 21 Exxon staff were evacuated by plane to Dubai, a security source said.
Zubair mayor Abbas Maher said the rocket was fired from farmland around 3-4 km (2 miles) from the site. A second rocket landed to the northwest of Burjesia, near a site of oil services company Oilserv, but did not explode, he said.
“We cannot separate this from regional developments, meaning the US-Iranian conflict,” Maher said.
“These incidents have political objectives ... it seems some sides did not like the return of Exxon staff.”
Exxon had evacuated its staff from Basra after a partial US Baghdad embassy evacuation in May and staff had just begun to return.
Burjesia is also used as a headquarters by Royal Dutch Shell PLC and Eni., according to Iraqi oil officials.
The officials said operations including exports from southern Iraq were not affected.
A rocket landed near the US 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.
Rockets hit on or near three separate military bases housing US forces near Baghdad and in the northern city of Mosul in three separate attacks since Friday.