Iraqi forces battling the Islamic State of Iraq and the Levant (ISIL) group for control of the northern town of Tikrit have encountered setbacks, with bombs and booby-traps slowing their advance.

"A rapid advance in a city where the ground is littered with bombs and booby-traps is too tough to achieve," said Mayor Osama al-Tikriti.

Security forces said on Sunday that they were slowly rolling into the city's western area with the help of US-led airstrikes despite Shia militias boycotting the offensive.

"There is some resistance from the enemy, but it's mainly due to the booby-traps set up on the roads, in the houses, shops and government facilities," Brigadier-General Thamer Mohamed told the Reuters news agency. "As you can see, our units are advancing and we have air support."

The security forces and Shia militias, who provided the largest number of fighters, began their offensive on March 2 but halted operations after two weeks due to heavy casualties and tensions within the government and with US officials over Iran's prominent role.



The battle remains slow-going. At least 17 security personnel have been killed in fighting and another 100 wounded around Tikrit since Thursday when the US airstrikes began, a security officer told the Reuters news agency.

On Sunday, an attempt to infiltrate Tikrit from the southern district of Shisheen was thwarted by rebels. They used anti-tank missiles to destroy a bulldozer being used by the military to clear a path around booby-trapped roads, an official said.

Meanwhile, several injured Shia fighters told Al Jazeera that the US was to blame for their injuries after striking their positions near Tikrit, the main city in Salahuddin provicence and birthpalce of Saddam Hussein, Iraq's fromer president.

Shia militias, aligned with Tehran, have repeatedly said they do not need US support to drive ISIL from Tikrit.

High stakes

Fighting to the south of Tikrit underscored the high stakes of the war against ISIL as even areas under government and militia control near Baghdad remain vulnerable to lightning-fast attacks by the fighters.



ISIL ambushed an Iraqi army and Shia paramilitary base near Dujail on Sunday, killing six paramilitary volunteers and wounding 14 others, a security official said.



The clashes in the countryside around Dujail, just 54km from Baghdad, lasted until sunset and involved two suicide bombers and machine gunners on pick-up trucks.



In Baghdad, at least seven people were killed in three bombings on Sunday, while a soldier also died in a bomb blast targeting a convoy in Tarmiyah just north of the capital.