Protesters entered a water treatment facility linked to the West Qurna 2 oilfield, managed by Lukoil, and held two Iraqi employees hostage on Friday, according to a Lukoil source and a source with Basra's energy police.
West Qurna 2 oilfield lies 65 km (40 miles) north-west of Basra - a city hit by days of protests. The field produces 390-400,0000 barrels per day and a disruption of three days would be enough to completely shut down the field, the Lukoil source added.
The water treatment facility maintains a supply of water to inject into the West Qurna 2 oil wells.