Iraqi special forces have launched a two-pronged assault deeper into Mosul's urban centre, unleashing the most intense street battles against Islamic State militants since the offensive began nearly three weeks ago.
Smoke rose across eastern neighbourhoods of Iraq's second-largest city as heavy fighting continued after sundown, with explosions and machine gun fire echoing in the streets as mosques called for evening prayer.
More than 3,000 Iraqi troops took part in the assault under heavy US-led coalition air support, but the pace of the fight also slowed as Iraqi forces moved from fighting in more rural areas with few civilians to the tight, narrow streets of Mosul proper.
Sniper fire repeatedly stalled the advance, as commanders called in air strikes or artillery support after coming under fire.
As the operation got under way, columns of armoured vehicles wound through the desert, pushing through dirt berms and drawing heavy fire as they closed in on the middle-class Tahrir and Zahara districts. The area was once named after former Iraqi dictator Saddam Hussein.
Seven suicide attackers in explosives-laden vehicles barreled towards the troops, with two getting through and detonating their charges, Lieutenant Colonel Muhanad al-Timimi said.
The others were destroyed, including a bulldozer that was hit by an air strike from the US-led coalition supporting the offensive.
At least seven special forces troops were killed and an officer and three soldiers were wounded, said an Iraqi military officer.
"The operation is going well, but it's slow. These kinds of advances are always slow," said Iraqi special forces Captain Malik Hameed, as IS fighters could be seen running in the distance to reposition themselves.
"If we tried to go any faster we would take even more injuries."
An Iraqi television journalist travelling in a Humvee was wounded in one of the suicide car bomb attacks.
Earlier, at the eastern approach to the city's urban centre, militants holed up in a building fired a rocket at an Iraqi Abrams tank, disabling it and sending its crew fleeing from the smoking vehicle.
The advance in that area then stalled.
The push began as dawn broke with artillery and mortar strikes on the Aden, Tahrir and Quds districts, just west of the special forces' footholds in the Gogjali and Karama neighbourhoods, Lt Col al-Timimi said.
On the heels of the special forces advances, the Iraqi army's ninth division moved into the eastern Intisar neighbourhood, said an officer from the unit.
On Tuesday, Iraqi troops entered the city limits for the first time in more than two years, after a demoralised Iraqi army fled in the face of IS's 2014 blitz across large swathes of territory in Iraq and neighbouring Syria.
The operation to retake Mosul is expected to take weeks if not months.
Moving from neighbourhood to neighbourhood in house-to-house battles through dense warrens of booby trapped buildings is time-consuming and Iraq's military has repeatedly opted for slower operations in an effort to minimise casualties.
Some one million civilians still remain in the city, complicating the advance.
IS militants have driven thousands of residents deeper into the city's built-up areas to be used as human shields, while hundreds of others have fled towards government-controlled territory and thousands have fled west into Syria.
Just a few miles from Friday's operation, dozens of cars queued up on the road to camps for displaced Mosul residents.
"We suffered and there was bombing and heavy shelling. We didn't feel safe," said Mahmoud Mahdi, who was fleeing the now government-held Gogjali neighbourhood. "Everybody is displaced and walking around in this heat. It is exhausting."
Mosul is the last major IS stronghold in Iraq, and expelling the militant group from the city would be a major blow to the survival of its self-declared "caliphate" that stretches into Syria.
Iraqi forces have made uneven progress in closing in on the city since the operation began on October 17.
Advances have been slower from the south, with government troops still some 20 miles (35 kilometres) away.
Kurdish fighters and Iraqi army units are deployed to the north, while government-sanctioned Shiite militias are sweeping in from the west to try to cut off any IS escape route.
As the sun began to set on Friday, special forces troops fanned out across the city blocks retaken in the fighting.
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Guided by intelligence from US-led coalition surveillance of the area, they knocked on the doors of homes where they believed civilians were living.
Moving from street to street, Capt Hameed and his men found four families and an elderly couple in the sector they were assigned to clear.
After sweeping the rooms for weapons, they questioned the male heads of household.
"Who were the IS fighters responsible for this neighbourhood?" special forces Major Ahmed al-Mamouri asked an elderly man.
"They were Arabs, but not Iraqi. Foreign," the man said, pointing to the houses where the fighters lived and worked.
As his children served the Iraqi soldiers tea, the man described where and when he saw the IS militants flee and the weapons they had.
Maj al-Mamouri pulled out satellite images of central Mosul and asked the man to identify checkpoints and buildings where he believed the fighters were making explosives.
"This is all to help with our operation moving forward," Maj al-Mamouri said.
"This is almost more important than the clashes."