Iraq has implemented an emergency plan to defend Baghdad as a representative for its most senior Shi'ite cleric urged people to take up arms and defend their country.
Sheikh Abdulmehdi al Karbalai, a representative for Grand Ayatollah Ali al Sistani, said "People who are capable of carrying arms and fighting the terrorists in defence of their country...should volunteer to join the security forces to achieve this sacred goal".
Islamist insurgents are edging closer to the country's capital after seizing large swathes of territory as they head south on the road from Mosul to Baghdad.
Along the way the fighters have been parading seized military equipment and flying the black and white flag of the Islamic caliphate, or state, they hope to create.
Security forces are gathering at a base just 20 miles outside Baghdad, ready to protect the city from Islamic State of Iraq and Syria (ISIS) fighters who have vowed to march on the city.
Brigadier General Saad Maan told the AFP news agency "The plan consists of intensifying the deployment of forces, and increasing intelligence efforts and the use of technology such as (observation) balloons and cameras and other equipment".
Insurgents have taken control of the northern cities Mosul and Tikrit, having previously seized Fallujah and parts of Ramadi.
The militants have also moved into the towns of Saadiyah and Jalawla in the eastern province of Diyala, after security forces abandoned their positions.
A security source and local official told Reuters that insurgents clashed with Shi'ite militia at two locations in the province.
Further assaults ready
The Iraqi army fired artillery at Saadiyah and Jalawla from Muqdadiya, 50 miles from the Baghdad city limits, sending dozens of families fleeing towards the Iranian border, security sources said.
The Iraqi air force also launched airstrikes on militant fighters' positions around Mosul and Tikrit.
Witnesses say the fighters are preparing a third assault on Samarra, 70 miles north of Baghdad, following two failed attempts to take the city.
As the chaos spreads, Iraqi Kurdish forces have taken control of Kirkuk, an oil hub close to their autonomous enclave, after government troops abandoned their posts.
Reporter Sherine Tadros, in Irbil, northern Iraq, said "The army right now is extremely demoralised, it feels like it's lacking in leadership and it's splintering under this pressure".
"Meanwhile, the militants certainly seem like they have the upper hand and all the momentum".
UN human rights spokesman Rupert Colville said the number of people killed in Mosul may run into the hundreds. He said his office had reports the killings included the execution of 18 civilians working for the police.
Four women killed themselves after being raped, while 16 Georgians have been kidnapped, Mr. Colville added.
"We've also had reports suggesting that the government forces have also committed excesses, in particular the shelling of civilian areas on 6th and 8th June" he said.
"There are claims that up to 30 civilians may have been killed".
Middle East Correspondent with The Guardian, Martin Chulov said residents are not taking any chances.
