The government has no capacity to process any more volunteers, he adds.

"No one knows when this battle will end, but we will win it," al-Shahristani insists.

The volunteers, who have pledged to join the nation's security forces to battle ISIL terrorists, gathered at the Federal Police Command headquarters across the country to sign up. They then set off in a convoy of trucks and buses towards the front line.

Millions of Iraqis including Shiites and Sunnis have heeded a call from the most revered spiritual leader, Grand Ayatollah Ali al-Sistani, to take up arms against the group, which has captured large areas of territory north of Baghdad.

The governor of a majority Shiite southern province said his region has already sent 5,000 volunteers to stem ISIL's advance in the north of the country.

The volunteers have headed to Balad and Samara - the most northerly major city still held by Iraqi forces - and to the outskirts of Mosul, Dhi Qar governor Yahya Baqer al-Nasiri told local news service Al-Mada Press.

Local sources said Samara was thronged with volunteers. The city 125 kilometers north of Baghdad is the site of one of Shiite Islam's holiest shrines.

Security officials reported clashes in various locations in Diyala and Kirkuk provinces, north of the capital.

Unidentified gunmen abducted 100 people in a raid on a vegetable market in Muweilaha, 60 kilometers south of Baghdad, and took them to an unknown location, a security official says.

The army was engaging gunmen in battle near Baquba, only 60 kilometers north-east of the capital, officials said.

In Tikrit, which fell to ISIL on Wednesday, conditions for residents were reported to be difficult after the terrorist groups took the control and destroyed many infrastructures including drinking water and electricity.

NJF/NJF