Shiite fighters gather to fight against ISIS militants in Baiji.

Iraqi forces defused booby traps and hunted down holdout jihadists in the strategic Baiji area Friday as part of their biggest advance against the Islamic State of Iraq and Syria (ISIS) group in months.

Baiji lies at a crossroads between several frontlines and control of the area is seen as the key to progress in other regions, including Anbar province where forces were also closing in on ISIS strongholds.

Iraq’s army, police and counter-terrorism services, as well as thousands of fighters from the Popular Mobilization (Hashed al-Shaabi), continued to gain significant ground in and around Baiji, officers said.

“Iraqi forces are moving deep into Baiji, they have retaken the industrial area and several other neighborhoods,” an army colonel told AFP.

“We control about 60 percent of the city, there are not so many Daesh fighters left and they are trapped,” he said, using an Arabic acronym for ISIS.

After retaking most of the refinery to the north of the city, security forces were sweeping the sprawling complex for bombs and die-hard jihadists.

“Inside the refinery, our forces are defusing booby traps and looking for the last Daesh terrorists we believe are still holed up in some buildings,” he said.

The refinery, which once produced 300,000 barrels per day of refined products meeting half of Iraq’s needs, is said to have been damaged beyond repair and to no longer be of huge strategic interest.

At least six anti-ISIS fighters were killed at the refinery on Thursday, several officers said.

The bodies of at least 15 ISIS fighters were also found there and large numbers of wounded jihadists are reported to have been evacuated to the nearby ISIS strongholds of Hawijah and Sharqat.

The same officer also said that Iraqi forces had completely surrounded Sinniya, a town west of Baiji on the road leading to Anbar.

“We are firing large numbers of rockets and missiles, while Iraqi warplanes are also striking. This will prepare the ground for an operation to cleanse Sinniya,” he said.

The operation launched this week to secure Baiji, which has seen almost uninterrupted fighting since IS swept across Iraq’s Sunni Arab heartland in June 2014, appears to be spearheaded by the Hashed.

Hadi al-Ameri, the most visible commander of the Hashed and a leading member of the Tehran-backed Shiite militia Badr, has been omnipresent on the Baiji frontlines.

Qassem Soleimani, commander of the foreign wing of Iran’s elite Revolutionary Guards, was also reported in Iraqi media to have played a key role.

The U.S.-led coalition, which is more active on the Anbar front, said Friday it had carried out two strikes in the Baiji area the previous day.

It also said it had destroyed parts of another refinery, in Qayyarah between Baiji and main northern city of Mosul, that “was used by Daesh to produce oil for the black market to fund their terrorist activities.”

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