Frightened Iraqi civilians hurry down a muddy street in Mosul as gunshots echo through the neighbourhood and a helicopter wheels overhead, firing a barrage of bullets towards jihadists below.

Others choose to stay, hanging white flags from their homes and periodically peering out as Iraqi forces battle the Islamic State group for control of the country's second city.

Children, some of them carrying plastic bags of belongings slung over their shoulders, are among those fleeing, as is a woman who weeps as she walks along the street.

Dozens more people move along the road leading away from the southeastern edge of the city, heading to a place where they pile into buses painted in police camouflage to be driven to safety.

"There was more movement of families (Friday)," says Lieutenant Colonel Hisham Abdulkadhim of Iraq's elite Rapid Response Division, a special forces unit that directed civilians to shelter as it advanced.

While the worst-case scenario of a million-plus people fleeing their homes during the battle to retake Mosul has yet to materialise, more than 120,000 people have been displaced since the operation was launched on October 17.

Mosul crackles with gunfire and explosions as the Rapid Response forces fight their way north alongside contingents from other units.

The advance is quick but careful, with an Iraqi army Humvee mounted with an anti-tank missile launcher on hand to target car bombs and a bulldozer that erects dirt barricades to block their approach.

Humvees provide cover for those on foot, who move alongside, weapons at the ready.

Helicopters prowl over the city firing bursts of gunfire and rockets, while the jihadists take aim at their aerial tormentors with small arms.

Some civilians open their doors to see what is happening, but the warning from Iraqi forces is always the same: go inside, close the door.

There are myriad dangers: a running infantry battle, jihadists with no qualms about endangering civilians, and air strikes, artillery fire and large, unguided rockets targeting IS.

Some of those who stayed in their homes in Mosul assist the advancing Iraqi forces.

- From fear to relief -

"A car bomb is behind the mosque," a federal policeman says, attributing the information to residents.

A mosque is visible over the rooftops less than 200 metres (yards) away.

A soldier looks for the car bomb through the sight of the Humvee-mounted missile launcher, but it does not appear, and a bulldozer builds a dirt berm across the street.

More civilians pour out of a nearby area, most on foot, though an old woman and several young children ride on a cart.

IS "forced us out," says Karama Attiyah, a distraught, black-robed woman carrying a blanket.

"They are hiding in front of us in our houses," she says.

Members of the Rapid Response forces direct the civilians into a building that has a white flag hanging from a wooden pole over its entrance.

After the quick advance and near-constant gunfire, the end seems to come suddenly as Iraqi forces reach their objective at the northern edge of the neighbourhood.

For civilians, hours if not days of fear turn to relief, and they begin to emerge from their homes without being told to remain inside.

Some boys jump up and down while flashing the victory sign, possibly imitating nearby security forces.

One little girl wearing a pink coat holds up a hand-drawn Iraqi flag, though it does bear the since-eliminated stars of the Baathist era of Saddam Hussein.

Mosul's inhabitants still reside in a broken, battleground city, and investigation into possible IS ties likely lies ahead for some of the men, but in this area, the immediate danger is over.

"This is the first time we went out in three days," says Hasna Yassin, a woman standing at the gate of one house.

Asked how she feels, Yassin says: "I was just reborn."