The escalation follows apparent attacks last week near the Strait of Hormuz on oil tankers, assaults that Washington has blamed on Iran.
A rocket was sacked at the headquarters of a number of global oil companies, including ExxonMobil, west of Basra, Iraq on Wednesday, injuring three Iraqi workers. In May, it evacuated staff from the West Qurna 1 oil field in Basra province. There was no immediate claim of responsibility.
There was no immediate claim of responsibility - but the blast comes two separate attacks in as many days on bases housing U.S. military personnel in Iraq, as tension rose between the United States and Iran.
As tensions escalate between Iran and the US, there're concerns Iraq could once again get caught in the middle.
Wednesday's rocket was the latest attack on an area housing USA interests. Royal Dutch Shell PLC and Italian Eni SpA also operate out of the site.
The Securities' sources said that Exxon plans to evacuate 20 foreign staff from Basra after oil headquarters hit by rocket.
Wednesday's incident came just as Exxon staff who were also evacuated after the diplomats' departure had begun to return to Basra.
According to security official Mahdi Raykan, a Katyusha rocket landed at dawn at a section of the camp of the Iraqi Drilling Company in the Zubair and Rumeila oil fields, where Exxon Mobil and other foreign oil companies also have caravans for workers.
The United States partially evacuated its embassy in Baghdad last month after the Trump administration accused Iran, without providing evidence, of supporting "imminent attacks" on US personnel in the region.
A foreign security guard protects ExxonMobil's expatriate and Iraqi staff of the West Qurna-1 oilfield, which is operated by the companyl, during an opening ceremony near Basra, Iraq, June 17, 2019.
Last Thursday, two explosions occurred on oil tankers in the Gulf of Oman.