Baghdad: Iraqi forces brace for a major offensive to retake control of Tikrit city, as the troops continued to battle insurgent groups across the country, security sources said.

The security forces have been holding control over the perimeter and entrances of Tikrit, 170 km north of the Baghdad, after seizing the areas around the city like Uojah town, lying south of Tikrit, said the Iraqi military spokesman Qassim Atta in Baghdad.

Separately in the northern Salahudin province, Sunni terrorists, claiming to be from Al-Qaida offshoot Islamic State (IS), carried out attacks to seize the strategic Baiji oil refinery near Baiji, 200 km north of Baghdad, but were repelled by the security forces, Atta said.