Iraqi Government forces are battling Islamic State militants near Fallujah, bombarding central districts at the outset of an offensive to retake the longtime jihadist stronghold on the western approaches to the capital Baghdad.
Some of the first direct clashes occurred in the area of al-Hayakil on Falluja's southern outskirts on Monday, a resident said.
Iraqi troops also approached the northern suburb of Garma, the top municipal official there said, to clear out militants before turning their attention towards the city centre.
Air strikes and mortars overnight targeted neighbourhoods inside the city where Islamic State is believed to maintain its headquarters.
Seven civilians and two militants were killed in the shelling, while 21 civilians and two militants were wounded, a source at Fallujah's medical centre said.
Iraqi military spokesman Brigadier General Yahya Rasool, speaking on state television, described the Government's advance as "careful" and reliant on engineers to dismantle roadside bombs planted by the militants.
Fallujah, a bastion of Sunni Muslim jihadists 50km from Baghdad, was the first city to fall to IS, in January 2014.
Six months later, the group declared a caliphate spanning large parts of Iraq and neighbouring Syria.
Iraqi forces have surrounded Fallujah since last year but focused most combat operations on IS-held territories further west and north.
The authorities have pledged to retake Mosul, the north's biggest city, this year in keeping with a US plan to oust IS from their de facto capitals in Iraq and Syria.
But the Fallujah operation, which is not considered a military prerequisite for advancing on Mosul, could push back that timeline.
There are between 500 and 700 IS militants in Fallujah, according to a recent US military estimate.
Prime Minister Haider al-Abadi announced the offensive in a late-night speech, saying it would be conducted by the army, police, counter-terrorism forces, local tribal allies and a coalition of mostly Shi'ite Muslim militias.
Iraqi and US officials estimate there are as many as 100,000 civilians still in Fallujah, a city on the Euphrates river whose population was three times that size before the war.
A six-month siege has created acute shortages of food and medicine.
The Baghdad government has called on civilians to flee, opening safe corridors to southern areas, but roadside bombs have prevented many from leaving.
The UN refugee agency UNHCR said 80 families managed to flee in recent days via a main road or through agricultural fields and were undergoing screening by the security forces.
At least three people had been killed trying to escape while 10,000 families were stuck inside "in a very precarious situation".
Residents living in central Fallujah moved at dawn to relative safety in outlying northern areas but IS patrols have since begun limiting movement even between neighbourhoods.
Militants were also using mosque loudspeakers to urge civilians to donate blood, residents said.