The air raids targeting Falluja, held by fighters opposed to the US presence in Iraq, centred on its northern neighbourhood, but no details were immediately available.
The US military has been relentlessly pounding the stronghold of fighters in recent days.
It says the strikes have eliminated scores of wanted fighters, but doctors at Falluja's hospitals say many of the victims of the raids are women and children.
Also on Monday evening US army helicopters launched air strikes against Baghdad's eastern suburb of Sadr City, the US military announced.
The raids followed bombing runs earlier on Monday which killed up to five people and wounded 46, including women and children.
Residents said loud explosions echoed throughout the night and US jets repeatedly swooped low over the sprawling suburb, home to many supporters of Shia leader Muqtada al-Sadr.
Dr Qasim Saddam of the Imam Ali hospital in Sadr City said five people were killed and 40 wounded, including 15 women and nine children.
At least two children wrapped in bloodstained bandages could be seen lying in hospital beds and one man suffered burns from head-to-toe.
Iraqi girl, Saja Rahim, seven, was
wounded in the attack
A US army spokesman had no immediate comment on the attack.
Aws al-Khafaji, head of the al-Sadr office in Nasiriya, told Aljazeera the Shia leader intended to issue a new peace initiative on Iraq's current situation.
US forces recently launched an extensive crackdown in Sadr City in an effort to subdue al-Sadr's al-Mahdi Army fighters.
Last Wednesday, 22 people were killed and 48 wounded in clashes in the slum area between fighters loyal to al-Sadr and US and Iraqi forces.
A car bomb exploded in the northeastern city of Mosul on Monday killing three policemen and injuring five others.
Armed assailants followed up the blast with a burst of automatic weapons fire before fleeing the scene, said Lieutenant-Colonel Salih Jamir, the patrol's commander.
Earlier on Monday, mortar bombs were fired at a police academy in eastern Baghdad, but there were no reports of casualties, the Interior Ministry said.
Spokesman Colonel Adnan Abd Al-Rahman said five mortar shells landed near the academy, causing no damage to the building.
The roadside bombing killed four
Iraqis and injured one
Elsewhere in the conflict-stricken country, four Iraqis were killed and one injured in a roadside bombing late on Sunday in the town of Khan Bani Saad, northeast of Baghdad on the road to Baquba, police and one of the injured said on Monday.
The men were farmers travelling in a pickup truck carrying petrol canisters for their own use when they hit a roadside bomb 20km south of Baquba, said an injured man, Falah Turki, who was driving the vehicle.
Police in Baquba confirmed the attack.
In northeast Baghdad, a US military Humvee was damaged on Monday when an explosive device targeting a US patrol detonated at the entrance of Miqdadiya city, Aljazeera has learnt.
US forces have cordoned off the explosion site, but made no mention of casualties.