The Islamic State group has launched a renewed push to seize Iraq's main oil refinery north of Baghdad, battling security forces backed by air support, authorities and witnesses said, Aljazeera reported.
At least three Iraqi security personnel were killed, and seven others were injured in the fighting on Sunday, in which fighters attacked the Baiji refinery from three sides, sources told Al Jazeera.
The attack on Sunday came as Iraq's next-door neighbour Iran reiterated its support for the new Shia-led government of Prime Minister Haider al-Abadi, with a visit from Iranian Foreign Minister Javad Zarif.
The fight over the oil field started overnight and continued into the next day, according to news reports.
The Islamic State fighters have repeatedly sought to overrun the refinery, which once accounted for about 50 percent of Iraq's supplies of refined oil products.
While they have previously managed to enter the refinery compound, security forces were able to push them back at this time.
The unrest has hit northern oil production and shipments, but Iraq's massive southern fields and export terminals remain unaffected.