Abdel-Wahab al-Saadi, the top military commander in Iraq’s Salahuddin province, said ground forces entered the Beiji oil refinery on April 18, days after a number of IS militants carried out a large-scale attack and briefly took over a small part of the complex.
"It is another victory achieved by Iraqi security forces that are growing confident in the war against the terrorists," al-Saadi told The Associated Press in a telephone interview.
The refinery has remained under government control, but the militants had been surrounding the entire complex preventing access by Iraqi forces.
A day earlier, Iraqi soldiers, backed by U.S.-led coalition airstrikes and Shiite and Sunni militias dubbed the Popular Mobilization Forces, gained control of the towns of al-Malha and al-Mazraah, located 3 kilometers (1.9 miles) south of the Beiji refinery.
Iraqi forces recaptured Tikrit, capital of Salahuddin, on April 1 and have been gradually pushing their offensive north to secure the rest of the province.
Militants from IS seized Ninevah province and much of Salahuddin and Anbar provinces last summer during their advance across northern and western Iraq.