The tomb of Iraq's late dictator Saddam Hussein has been virtually levelled in heavy clashes between militants from the Islamic State in Iraq and Syria (ISIS) and Iraqi forces in a fight for control of the city of Tikrit.

Fighting intensified to the north and south of Saddam Hussein's hometown Sunday as Iraqi security forces vowed to reach the centre of Tikrit within 48 hours. Associated Press video from the village of Ouja, just south of Tikrit, shows all that remains of Hussein's once-lavish tomb are the columns that held up the roof.

Poster-sized pictures of Saddam, which once covered the mausoleum, are now nowhere to be seen amid the mountains of concrete rubble. Instead, Shia militia flags and photos of militia leaders mark the predominantly Sunni village, including that of Maj.-Gen. Qassem Soleimani, the powerful Iranian general advising Iraqi Shia militias on the battlefield.

"This is one of the areas where IS militants massed the most because Saddam's grave is here," said Capt. Yasser Nu'ma, an official with the Shia militias, formerly known as the Popular Mobilization Forces. "The IS militants set an ambush for us by planting bombs around" the tomb.

Lightning offensive

ISIS has controlled Tikrit since June, when it waged its lightning offensive that saw Iraq's second-largest city, Mosul, come under their control. The extremist group was helped in its conquest of northern Iraq by Saddam loyalists, including military veterans, who appealed to Sunnis who felt victimized by Baghdad's Shia-dominated government.

ISIS claimed in August that Saddam's tomb had been completely destroyed, but local officials said while it was ransacked and burned, it had suffered only minor damage.

We want to take revenge on those IS militants who killed our children. - Yazan al-Jubouri, a Sunni fighting alongside Shia militias

Saddam was captured by U.S. forces in 2003 and was executed by hanging in December 2006 after an Iraqi special tribunal found him guilty of crimes against humanity for the mass killing of Shias and Kurds. His body has been kept in the mausoleum in his birthplace, Ouja, since 2007. The complex featured a marble octagon at the centre of which a bed of fresh flowers covered the place where his body was buried. The extravagant chandelier at its centre was reminiscent of the extravagant life he led until U.S. forces toppled him in 2003.

Iraqi media reported last year that Saddam's body was removed by loyalists amid fears that it would be disturbed in the fighting. The body's location is not known.

Iraqi security forces and allied Shia militiamen clash with ISIS fighters at the front line in the Qadisiyah neighbourhood in Tikrit, 130 kilometres north of Baghdad. (Khalid Mohammed/Associated Press) Recapturing Tikrit, a Sunni bastion on the Tigris River, would pave the way for an assault on Mosul, which U.S. officials have said could come as soon as next month.

Concerns are mounting that Iraq's Shia militias, of which an estimated 20,000 are fighting in Tikrit, will carry out revenge attacks on this and other areas that are home to predominantly Sunni residents.

Tikrit heavily damaged

Tikrit has already been heavily damaged in months of violence. A satellite image of Tikrit, released last month by the United Nations, observed that at least 536 buildings in the city have been affected by the fighting, with at least 137 completely destroyed and 241 severely damaged.

Local Sunni tribal fighters have formed uneasy alliances with the Iraqi army and Shia militias in the battle for Tikrit, which Iraqi and U.S. officials believe is essential for defeating the Sunni militant group.

Yazan al-Jubouri, a Sunni from Tikrit fighting alongside the Shia militias, said ISIS militants killed 16 of his relatives.

"We want to take revenge on those IS militants who killed our children," he said.