Oil prices have risen following the suspected sabotage which closed Iraq's pipeline to Turkey only two days after it was reopened.
North Sea Brent crude - a benchmark for world oil prices - rose 35 cents a barrel to 29.16 US dollars as dealers worried that the disruption would hit supplies.
Friday's pipeline explosion is just the latest event to affect the volatile world oil price this year. Prices rose rapidly in the run-up to war in Iraq before dipping again on the conclusion of major fighting.
But traders said, in contrast to market expectations, oil prices had shown healthy year-on-year increases despite the short-lived recovery in Iraqi exports.
Iraqi exports had trickled to a stop with the US-led invasion until the pipeline reopened last week. The new flow of oil had been expected to help subsidise the reconstruction of the country.
The pipeline, linking the giant oilfields at Kirkuk to the Turkish terminal at Ceyhan, accounted for around a third of Iraq's pre-war oil exports of 2.4 million barrels a day.
Estimates from the US administration in Iraq have put the cost of the pipeline sabotage at around seven million US dollars (£4.3 million) a day in lost revenue.
The pipeline is expected to take between 10 days and four weeks to repair.