"The minister was going to attend a ceremony in Baiji when a roadside bomb exploded," on Monday, the minister's spokesman Assem Jihad said.


He added that the minister's convoy was heading for Baiji, a refining town 180km north of the capital.


"The minister is fine and is now at the ministry in a meeting with his staff," he added.


Jihad said he knew of two bodyguards who were killed and two seriously wounded when two of the cars in the convoy were destroyed in the Rashdiya district of northern Baghdad.


A police source later said three guards had died.


Iraq's oil industry, which has the world's third-largest known reserves, has been crippled by war, sanctions and the uprising among minority Sunni Arabs.


Production remains limited, curbed by decaying infrastructure and sabotage, but oil provides the main hope of prosperity for the country.