BAGHDAD, IRAQ - Iraqi security forces launched an operation Monday to retake the city of Fallujah from Islamic State extremists, storming the stronghold from various points, military leaders said.
VOA spoke by telephone to an Iraqi special forces soldier on the front line of the Fallujah battle.
"The Iraqi special forces and special operations are entering the city and clearing it block by block and then handing the cleared areas over to the Iraqi police, army and volunteers," he said, speaking through a translator.
Volunteers refers generally to the Hashd al Shaabi, an umbrella group of mostly Shi'ite militias.
"Step-by-step we are putting up the Iraqi flag ... there are a lot of dead, including Iraqi special forces and Iraqi special operations soldiers. They are dying by mortars and sticky bombs. The war is not face-to-face, it is by mortars, car bombs and snipers," the soldier said.
He also said many IS fighters have been killed, but some have been captured alive and are providing information.
As the battle started, there are concerns over the plight of civilians trapped inside the Islamic State held city.
"They [IS] have put bombs in the roads, they are using suicide bombers," said Muhamed, an Iraqi special forces soldier on the front line contacted by telephone, speaking on condition his full name not be used.
WATCH: Concerns grow over civilian suffering in Fallujah
Fallujah, a Sunni stronghold, has been held by IS longer than any other city in Iraq and the fighters are believed to be deeply entrenched in the city.
"We are just waiting for the order to move in, and kill Daesh," he said, using the Arabic name for Islamic State.
As the fighting and airstrikes around the city have intensified, the plight of civilians trapped inside has worsened. While some 800 people have managed to escape, thousands of others have not.
UNHCR says it is receiving reports of horrific civilian suffering.
WATCH: UNHCR expresses concerns
"We have dramatic report of increase in the number of executions of men and older boys unwilling to fight on behalf of ISIL," UNHCR spokeswoman Melissa Fleming said.
"Other reports say that a number of people attempting to depart have been executed or whipped. In addition, many people have reported to have been killed or buried under the rubble of their homes in the course of ongoing military operations," Fleming said.
Humanitarian agencies have repeatedly called for the civilians to be allowed to leave the city.
Those who have managed to escape are separated, with the men and older boys taken to special security screening locations.
There is a lot of suspicion in Baghdad surrounding those Fallujah residents who have been under IS control for more than two years.
"They are brainwashed by now," said one Iraqi federal police officer who would only give his initials as H.K. as he was not allowed to speak to the press. "They should be placed in a special camp."
Fallujah has been under siege for six months, with very little food or medicine entering the city.
One displaced woman who gave her name as Alahin told UNHCR of the horrors of the last few months.
"Families started to suffer when (IS) closed the exit routes from the city," she said. "Families started suffering from psychological problems and some of them committed suicide. Some of them set fire to themselves and some of them drowned their children.
"As God is my witness, everything I say is true," she said.
It was not possible to immediately verify any of the reports.