Thousands of soldiers and government-backed Shi'ite militias already claim to have killed ISIS' second in command in the city, which is the birthplace of former Iraqi dictator Saddam Hussein.

The anti-ISIS advance has been slowed by numerous roadside bombs however, leading to fierce clashes outside the town of al-Dour, south of Tikrit.

Retaking the ISIS stronghold is considered vital if government forces are to succeed in their plan to force ISIS out of the oil rich city of Mosul, the terror group's Iraqi power base which lies just 140 miles north of Tikrit on Highway 1 - a road that effectively marks the front line in northern Iraq.

Despite reports of local successes and the killing of ISIS' local second in command, officials in northern Iraq say troops are still clashing with jihadis south of Tikrit.

Roadside bombs, the officials claim, have slowed the offensive to retake the ISIS-held city.

The two local officials say fierce clashes are underway outside the town of al-Dour, south of Tikrit.

They say government forces backed by Shi'ite militias and Sunni tribal fighters have made little progress on the second day of a large-scale military operation to recapture Tikrit, which fell to the Islamic State group last summer. 

They say troops are shelling militant bases inside the city but their advance has been slowed by roadside bombs. The officials spoke anonymously as they are not authorized to brief media. 

(dailymail.co.uk)