- 20,000 Iraqi troops and fighters attack ISIL positions in Tikrit from three fronts
- Troops reportedly in process of retaking neighbourhoods in Tikrit's northeast
- Tens of ISIL fighters killed in Tikrit offensive, state media reports
- Advance of Iraqi troops is slowed due to roadside bombs and booby trapped homes
Iraqi government forces backed by allied Shia and Sunni fighters have begun a large-scale military operation to recapture Saddam Hussein's hometown from the Islamic State of Iraq and the Levant (ISIL) group.
A force comprising 20,000 soldiers and fighters was trying to advance into Tikrit on Monday to force the armed group from the historic city and the surrounding Salahuddin province, north of Baghdad.
State-run Al Iraqiya TV channel said that forces were attacking Tikrit, 130km north of Baghdad, from different directions, backed by artillery and air strikes by Iraqi fighter jets.
Iraqi security forces said they have now retaken control of al-Dour, including the countryside where former President Saddam Hussein was found hiding, Al Jazeera's Jane Arraf reported from Baghdad.
"This is the first test for the Iraqi military," she said.
The military commander of Salahuddin, General Abdul-Wahab al-Saadi, told state TV the operation was "going on as planned", with fighting taking place outside Tikrit mainly on its eastern side.
On Sunday, Haider al-Abbadi, the Iraqi prime minister, travelled to Samarra to rally the troops.
"Our goal is to liberate people from the oppression and terrorism of Daesh," he said in a televised address, referring to the Arabic acronym used to describe ISIL fighters.
He later returned to Baghdad to meet members of parliament.
Tikrit, the provincial capital of Salahuddin, fell to ISIL last summer, along with the country's second-largest city of Mosul and other areas in the country's Sunni heartland.
Past attempts to retake Tikrit have failed, however, as Iraq struggles with its armed forces, which collapsed in the wake of an ISIL offensive last summer.
The city was an early centre of the armed campaign against the US military and a base of opposition to subsequent Iraqi governments.
Like most Sunni majority areas, many in the province believe they have been marginalised by the Iraqi government and mistreated by Iraqi security forces.
| Al Jazeera's Imran Khan reported on the fighters who are now going into Tikrit [February 15]
ISIL's most effective Iraqi ally is believed to be a group headed by Saddam’s elderly former right-hand man, Izzat Ibrahim al-Douri, from al-Dour, southwest of Tikrit, our correspondent said.
Iraqi military officials told Reuters news agency that about 2,000 Shia fighters had arrived near Tikrit in preparation for the major operation.
Raed Salahuddin, governor of Salahuddin, had said last week that 5,000 fighters from the security forces and Hashid Shaabi militia, which was formed last year with Iranian support, would join the operation.
Al Jazeera's Arraf said: "This is one of the biggest military operations that will eventually proceed to take back Mosul," referring to the main city of Nineveh province, which is a stronghold of ISIL.
She said US air strikes were expected to provide back-up for the Iraqi troops on the ground.
"This is not expected to be an easy fight," she said. "ISIL has dug in there".
In advance of the ground operation, ISIL fighters launched pre-emptive strikes on Saturday against targets in Samarra.
After months of air strikes by the US and its Western and Arab allies, ISIL is on the defensive in several parts of the "caliphate" it declared in swaths of Iraq and Syria.
Source: Al Jazeera and agencies