Iraqi officials said the Islamic State (IS) militant group has launched a large assault on the city of Ramadi, the provincial capital of Anbar on April 10.
The militants attacked the northwest and southwest part of Ramadi.
Security officials said the attack in the northwest was reportedly repelled by security forces supported by air strikes.
In southwest Ramadi suicide car bombers targeted security forces at the entrance to the city, breaking a hole in defenses that allowed some IS militants to enter the city, the officials said.
At least 13 IS militants were killed in that fighting, the officials said.
The Iraqi government was reportedly rushing reinforcements to Ramadi in preparation for counterattacks.
The IS assault came a day after Prime Minister Haidar al-Abadi said Iraq's "next battle" is to retake Anbar, most of which is controlled by the IS group.
Security sources said IS militants executed dozens of Sunni Iraqis in retaliation as Iraqi forces launched a new offensive there.