Production at the oilfield was not affected by the evacuation and work is continuing normally, overseen by Iraqi engineers, state-owned South Oil Company chief Ihsan Abdul Jabbar said, adding that production remains at 440,000 barrels per day.
"Exxon Mobil's evacuation is a precautionary and temporary measure. We have no indication over any dangers, the situation is secure and very stable at the oilfield which is running at full capacity and producing 440,000 bpd," he said.
"The foreign engineers will provide advice and perform their duties from the company's Dubai offices and we have no concerns at all," Jabbar said, adding that production is managed by Iraqi engineers and the foreign staff were there mainly as advisers.
The United States on Wednesday pulled non-emergency staff members from its embassy in the Iraqi capital Baghdad out of apparent concern about perceived threats from neighbouring Iran, to which Iraqi Shi'ite militias are allied.
Exxon Mobil's staff were evacuated in several phases late on Friday and early on Saturday, either straight to Dubai or to the main camp housing foreign oil company employees in Basra province.
Those in the camp were en route to the airport on Saturday morning, sources - including an employee at a security company contracted by Exxon, Iraqi oil officials, and a staff member of a foreign oil company - said.
"Last night 28 employees were evacuated to the airport and the rest were sent to the camp. This morning they were evacuated to the airport and no (foreign) staff remain in the field," said a private security company official who oversaw the evacuation.
Days of sabre rattling between Washington and Tehran have heightened tensions in the region amid concerns about a potential U.S.-Iran conflict.
Washington has increased economic sanctions and built up its military presence in the region, accusing Iran of threats to U.S. troops and interests. Tehran has described those steps as "psychological warfare" and a "political game".
Separately, Abdul Jabbar said that Iraq's oil exports from its southern ports had reached 3.5 million bpd by Saturday.