Iraqi militants have taken control of the northern city of Mosul on Tuesday.
Following the incident, Iraq's prime minister has asked parliament to declare a state of emergency, BBC reported.
The report said hundreds of armed men have seized the provincial government's offices overnight.
They also destroyed several police stations before overrunning the airport and army's operations headquarters.
Meanwhile, a double bomb attack in Baquba has killed at least 20 people.
Militants from ISIS have been informally controlling much of Nineveh province for months.
After five days of fighting, they took control of key installations in the provincial capital, Mosul, which has an estimated population of 1.8 million.
A government employee Umm Karam said: "The situation is chaotic inside the city and there is nobody to help us. We are afraid."
Many police stations are reported to have been set on fire, local TV stations showed pictures.
