Iraqi forces pressed Saturday their biggest offensive in months to resume their long-stalled northward advance and disrupt militants lines

Iraqi forces pressed Saturday their biggest offensive in months to resume their long-stalled northward advance and disrupt militants lines, security officers said.

After recapturing parts of Baiji and the huge nearby refinery complex from the ISIL terrorist group, security and allied paramilitary forces thrust further northward up the main highway leading to Mosul.

They reached the town of Zawiyah and vowed to push on to Sharqat, the northernmost town in Salaheddin province before the border with Nineveh province, of which Mosul is the capital.

"Iraqi forces are besieging the villages of Msahaq and Zawiyah," about 25 kilometers (16 miles) north of Baiji, a senior officer in Salaheddin operations command said.

Reclaiming control of that stretch of road and the villages along it would contribute to isolating ISIL strongholds east of the Tigris, such as Hawijah, from the self-proclaimed caliphate's heartland on the other side of the river.

"Retaking Zawiyah would divide the battlefield; Daesh will be in an awkward position," retired general and security analyst Abdel Karim Khalaf said, using an Arabic acronym for ISIL.

"Their transport towards Tikrit and Ramadi will be complicated, the secondary itineraries are long and difficult," he said.

Iraqi forces, including thousands of fighters from the Popular Mobilization organization, were still battling ISIL in and around Baiji Saturday.

Further west along the Euphrates, Iraqi troops were fighting to retake the town of Baghdadi.