Iraqi troops have continued fierce battles with Islamic State of Iraq and the Levant (ISIL) fighters on the outskirts of Tikrit, as they try wrest control of the city from the armed group, security officials said. 

Army forces and Shia militia exchanged fire with ISIL fighters in clashes on Sunday in the western section of al-Dour, on the southern edge of Tikrit, officials told the Reuters news agency.

Military commanders said the army and Hashid Shaabi militia group units launched an offensive late on Saturday to break into the centre of al-Dour.

By Sunday they had succeeded in recapturing the central area of town, where government headquarters are located, but ISIL fighters were still holding positions in the west.

Al-Dour is the town where slain leader Saddam Hussein was hiding when he was found in a pit near a farmhouse in 2003 and captured by US forces.

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Government troops have also reportedly captured the village of Albu Ajil, which is also in the south of Tikrit.

Some Albu Ajil residents were accused by authorities and Shia militia groups of taking part in the killing of soldiers from the nearby Speicher army camp when ISIL overran Tikrit and northern Iraq last June.

Shia militia fighters have described the advance on Albu Ajil as revenge for the Speicher killings, although militia leaders say all civilians in the Sunni Muslim region will be well treated. 

The campaign to retake Tikrit is the biggest offensive so far against ISIL. If successful, it would be the first time the army and militia have recaptured a major city from the armed group.

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Progress in the offensive, which was launched a week ago, could also affect the timing and strategy for a wider offensive later this year to retake Mosul, the largest city under ISIL control.

A potential Mosul operation on Sunday got backing from influential Iraqi Shia cleric Muqtada al-Sadr who said his militia would take part in the offensive.

His forces fought against the US military after they invaded Iraq in 2003. But the former enemies could now join forces, as the operation to recapture Iraq's second-largest city is expected to be accompanied by air support from the US-led coalition.

The offensive is expected to be a joint operation also involving the Iraqi army, Kurdish Peshmerga troops and local tribes.

Baghdad bombings

Elsewhere in Iraq, a series of bombings targeting public places and police killed 11 people around Baghdad on Sunday. 

Police officials said the first of Sunday's attacks happened when a car bomb exploded in a parking lot in the town of Mahmoudiya, 30km south of Baghdad, killing three people and wounding 15 others.

Later on, a bomb blast in a commercial street killed three people in Baghdad's northern suburb of Husseiniyah. Another blast in a town just south of Baghdad killed two people and wounded nine others.

Police said a roadside bomb missed a police patrol in eastern Baghdad, killing three civilians.

Source: Al Jazeera and agencies