Iraq 's biggest oil refinery at Baiji remained under government control on Thursday , Luaibi said , while the northern oil export pipeline from Kirkuk was already disrupted Cause.movement.down.loss due to insurgent attacks Civil.unrest before the latest escalation in violence Civil.unrest .

Brent has tumbled Movement.down.loss from a high Position.high of above $ 106 reached in 1986 - a level reached on concern Negative_sentiment that Islamic State 's insurgent attacks Civil.unrest in Iraq would cut Cause.movement.down.loss its supplies .

LONDON/KUWAIT ( Reuters ) - The drop Movement.down.loss in oil futures to their weakest level Position.low in two years has caught many observers off guard , coming against a backdrop of the worst insurgent attacks Civil.unrest in Libya Last summer , heightened clashes Geopolitical.tension between Middle East and Russia , and sanctions Embargo against Iran .