Iraqi forces drive ISIS out of Baiji and begin siege of its oil refinery Iraq has recaptured Baiji, 130 miles north of Baghdad, from ISIS North of Baiji is Iraq's main oil refinery, which is still under ISIS control The city of Baiji and the refinery was captured by ISIS in June this year Iraqi forces have recaptured the city of Baiji in a significant victory over ISIS after more than two weeks of fighting. Baiji is the largest city to be retaken by government troops since ISIS-led militants overran much of Iraq's Sunni Arab heartland in June in their bid to create an Islamic 'caliphate'. The recapture is also strategically important as Iraq's largest oil refinery, capable of producing 300,000 barrels of refined petroleum products per day, is located just outside of the city. Liberated: ISIS militants took the northern Iraqi city of Baiji in June (pictured) but the important oil-town has now been recaptured by Iraqi troops Baiji is located 130 miles north of Baghdad on the main highway Mosul, and had been under ISIS control since June. Although ISIS still controls the oil refinery, the recapture of Baiji further isolates militants farther south in the city of Tikrit, although IS still controls large parts of Iraq as well as swathes of Syria. 'Iraqi forces were able to regain complete control of the town of Baiji,' Ahmed al-Krayim, the head of the Salaheddin provincial council said. Soldiers, police, Shiite militiamen and tribesmen were all involved in the operation to retake Baiji, and are now pushing farther north. Iraqi forces are on their way to the Baiji refinery where security forces have held out against repeated jihadist attacks. Black gold: Baiji is strategically important as Iraq's largest oil refinery is located just outside of the city The Iraqi town of Baiji is located near Iraq's main oil refinery on the main highway to the Islamic State-controlled city of Mosul An Iraqi soldier walks through Jurf al-Sakhr after regime forces retook the town from ISIS militants last month Breaking through to the massive refinery would be another significant win for the government in Baghdad. But the victory was marred by a suicide bombing Friday that targeted a military command headquarters set up at Tikrit University, south of Baiji, killing at least four people, army officers said. Three suicide bombers and other militants had attacked the same headquarters in late October, disrupting the initial push into Baiji. ISIS also claimed a truck bombing in Baiji that killed a senior police officer last week. Iraqi troops initially struggled to regain ground from IS after the start of the jihadist offensive. In control: Armed trucks used by ISIS can be seen taking up position near a market in central Mosul, northern Iraq, on Thursday An ISIS fighter is seen securing a street in central Mosul, the day before Baiji was recaptured by Iraq With help from US-led air strikes, support from Shiite militias and Sunni tribesmen, assistance from international advisers, and a signficant reshuffling of top officers, Baghdad's forces have begun to make progress. The operation to retake Baiji began more than four weeks ago when security forces and pro-government fighters started advancing towards the town from the south, slowed by bombs militants had planted on the way, and finally entered on October 31. The nearby Baiji refinery once produced some 300,000 barrels of refined petroleum products per day, meeting 50 per cent of the country's needs, but even once it is recaptured, it would take time before it could resume production.