Extremist militants were using armored vehicles and suicide bombings in their biggest attempt so far to capture the Baiji refinery, around 200 kilometers north of the capital Baghdad, an official told DPA on Sunday.
"The Iraqi security forces, in charge of guarding the refinery, were able to thwart the attack that started last night," added the official on condition of anonymity because he was not authorized to speak to the media.
At least 30 militants had been killed in the fighting, according to the official.
"Their bodies are still lying near the walls of the refinery as clashes continue to break out nearby."
He said that government warplanes had backed the security forces on the ground in repulsing the extremists' attack.
NTJ/HH