Following the attack on military and oil sites, no one claimed responsibility for the rocket fire that began last Friday, but Iraq has expressed on several occasions fears over the tension between Tehran and Washington will be reflected on its territory.
Observers say such deterioration is not ruled out in a country where political leaders or armed groups have accused allegiance to different countries including Iran, Turkey, Saudi Arabia and the United States.
In the latest attacks, the security information cell revealed in a statement, "a Katyusha rocket fell on the firm drilling oil wells in the area of Burjisiyah, Basra, wounding three people as a preliminary result" at dawn on Wednesday.
For his part, the spokesman of the Ministry of Oil Assem Jihad told AFP that the wounded Iraqis were treated for minor injuries, adding that " Burjisiyah" is located several kilometers away from the oil sites where local and foreign firms are working."
There are compounds belonging to local and foreign oil firms in the Burjisiyah area, according to the spokesman.
Eighty-three foreign workers resumed work three weeks ago at Qurna oilfield in Basra after being pulled out of the country following escalating tensions between Iran and the United States.
"ExxonMobil's 83 expatriate employees will be back on Sunday," Jihad said earlier.
Hours before the Burjisiyah incident, the Joint Operations Command announced that a Katyusha rocket had hit the Nineveh Operations Headquarters in Mosul, but Nineveh's operations later confirmed that the rocket was homemade.
Local sources spoke of the presence of US troops in the same place.