BASRA, Iraq/DUBAI (Reuters) – Exxon Mobil has evacuated all of its foreign staff, around 60 people, from Iraq’s West Qurna 1 oilfield and is flying them out to Dubai, a senior Iraqi official and three other sources told Reuters on Saturday.

The evacuation came just days after the United States withdrew non-essential staff from its embassy in Baghdad, citing a threat from neighbouring Iran, which has close ties to Iraqi Shi’ite militia.

Production at the oilfield was not affected by the evacuation and work is continuing normally, overseen by Iraqi engineers, said the chief of Iraq’s state-owned South Oil Company which owns the oil field, Ihsan Abdul Jabbar. He added that production remains at 440,000 barrels per day (bpd).

“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.

Exxon Mobil is the lead contractor in a long-term deal with Iraq’s South Oil Company to develop and rehabilitate the oil field to increase its production. Exxon declined to confirm the evacuation.

“As a matter of practice, we don’t share specifics related to operational staffing at our facilities,” said spokeswoman Julie King.

“ExxonMobil has programmes and measures in place to provide security to protect its people, operations and facilities. We are committed to ensuring the safety of our employees and contractors at all of our facilities around the world.”

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, said Iraqi oil officials and a staff member of a foreign oil company.

“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.

Iraq sent an official letter to Exxon asking about the work hours of staff in Dubai and when they would return to the oilfield, because their absence affects costs and salaries, Abdul Jabbar said in an interview.

“There are over 1,700 people working in the oilfield, 1,300 are South Oil Company staff and 400 are Iraqis working with foreign companies. Only around 60 people have left and they’re all advisors, administrators and finance staff.”

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 said it was building 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.