Iraqi officials say their security forces have reached the Baiji oil refinery after driving out Islamic State (IS) fighters from the area.
Gen Abdul Wahab al-Saadi told Iraqi state TV that this could be the “main key in liberating each span of Iraq”.
The refinery, Iraq’s largest, was besieged by IS for five months.
IS seized large swathes of Iraq almost unopposed in a June advance and has been the target of a US-led air campaign since August.
Police Colonel Saleh Jaber, from the Baiji refinery protection force, told Reuters news agency that an Iraqi “anti terrorism” force called the Mosul Battalion had entered the refinery on Tuesday.
IS fighters had first laid siege to the Baiji refinery in June after taking control of the nearby town of Baiji in a lightning advance through northern Iraq.
