BAGHDAD (Reuters) - Exxon Mobil's decision to evacuate its foreign staff from the West Qurna 1 oilfield in southern Iraq on Saturday was "unacceptable and unjustified", Iraq's Oil Minister Thamer Ghadhban said on Sunday.

"The withdrawal of multiple employees - despite their small number - temporarily has nothing to do with the security situation or threats in the oilfields in of southern Iraq, but it's for political reasons," Ghadhban said in a statement.

Exxon Mobil, which has a long term contract to improve the oilfield on behalf of Iraq's state South Oil Company, withdrew all foreign staff, around 60 people, Iraqi officials have said.

The evacuation came just days after the United States withdrew non-essential staff from its embassy in Baghdad, out of apparent concern about perceived threats from Iran, which has close ties to Iraqi Shi'ite militia.

Ghadhban said he sent a letter to Exxon Mobil asking for the company to immediately return to work at the southern oilfield, ahead of a meeting with company executives later this week.

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

(Reporting by Ahmed Rasheed; Writing by Raya Jalabi; Editing by Peter Graff and Louise Heavens)