A bomb has been blamed for a fire at a key pipeline in northern Iraq, cutting off oil exports just three days after they had resumed. The US-appointed interim Oil Minister in Iraq said it would be several days before the pipeline was back in order.

?We believe at this stage it was an explosive device planted on the pipeline,? Thamir Ghadban told reporters. The fire, which burned for 24-hours, engulfed a section of the pipeline at Baiji, north of Tikrit ? the hometown of ousted President Saddam Hussein.

The export of oil from northern Iraq is a crucial factor in America?s post-war reconstruction plans for the country. The pipeline ? which carries oil from the northern oil city of Kirkuk to a Turkish terminal at Ceyhan, was only reopened on Wednesday for the first time since the invasion of Iraq in March.

The pipeline had been targeted by saboteurs or looters over the past few days, US military sources said. It is the main conduit from the giant Kirkuk oil fields, which produce 40 % of Iraq?s oil. Ghadban said he did not know who had carried out the sabotage.

?Security void?

?What is definite is that they were endeavouring to stop oil flows to the refinery (...) and to stop exports,? he told. He said there was a problem with security in Iraq, although he stopped short of criticising the US-led administration. ?In the past regime, we had the oil police, the army and the co-operation of the tribes, as well as what we call internal security,? he told. ?Now all this has disappeared. There is a void in security.?

Engineers had worked for months to get the pipeline working again. Like all of Iraq?s crumbling network, the pipeline was dilapidated by more than a decade of United Nations economic sanctions.

Pipelines have burst because of corrosion and they have been punctured by looters trying to steal oil. The US is hoping to bring output from Iraq?s northern oil fields up to 770,000 barrel per day by the end of the year ? still 50,000 barrels short of Iraq?s daily pre-war output. Flows through Iraq?s other export route, via the Mina al-Bakr oil terminal in the south, have been interrupted this week by power shortages.