Iraqi special forces meet resistance from ISIL fighters who attack in the east with a ferocious counter-assault.

ISIL fighters launched ferocious counter-attacks on Saturday in territory Iraqi special forces captured in Mosul’s eastern edges, highlighting the tough battle ahead as troops push into densely populated neighbourhoods.

ISIL emerged from deeper in the city to target Iraqi soldiers with mortars and suicide car bombs. It also attacked the southern edge of the Gogjali district, which Iraqi forces declared “liberated” earlier this week, pushing back some gains.

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Street battles continued, with both sides firing mortar rounds and automatic weapons at each other’s positions while Iraqi troops also responded with artillery.

Clashes were most intense in the al-Bakr neighbourhood. Sniper duels played out from rooftops in the mostly residential areas, where the majority of buildings are two storeys high.

Lieutenant-Colonel Saad Alwan, from Iraq’s counterterrorism unit, told Al Jazeera the street battles were vicious.

“We’re facing fierce resistance. They’re digging trenches and using car bombs,” Alwan said.

More evidence of daunting fortifications emerged on Saturday, with satellite images showing ISIL had set up defences to bog down advancing forces, including rows of concrete barricades, earth berms, and rubble blocking key routes leading to the centre of the city.

Slow southern advance

Advances towards Mosul have been slower from the south with government troops still 35km away, yet some progress has been made, Iraqi forces say. They assaulted ISIL positions in the town of Hammam al-Alil on Saturday, which lies along the Tigris river about 15km from the southernmost parts of Mosul.

Kurdish television channel Rudaw broadcast live footage of Iraqi troops and armoured vehicles amassing outside the city as an attack helicopter fired rockets.

Truckloads full of as many as 1,600 civilians may have been forcibly moved from Hammam al-Alil to Tal Afar earlier this week, and may be transferred onwards into Syria for possible use as human shields, the office of the UN High Commissioner for Human Rights warned on Friday.

Another 150 families from the town were moved to Mosul itself, it said.

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Iraqi Prime Minister Haidar al-Abadi, on what state television said was a visit to forward lines near Mosul, urged ISIL fighters to surrender.

“My words to the terrorists are that if you wish to save your lives, you should lay down your weapons. There is no place for you in Iraq,” said Abadi, surrounded by soldiers dressed in black from the counterterrorism unit.

“My message to the people in Mosul: Be ready, any minute now we will enter Mosul and cut off the head of the ISIL snake.”

Mosul is the only major Iraqi city still held by Islamic State of Iraq and the Levant, also known as ISIS, which seized control of the city in 2014.

Last month, Iraqi troops and special forces, Shia militias, Kurdish Peshmerga fighters, and other groups backed by US-led air raids launched a campaign to retake the city.

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Meanwhile, an aid agency said on Saturday that the number of displaced people had risen sharply, with more than 9,000 new arrivals in camps outside the city.

“This is the beginning of a massive exodus from Mosul city,” Wolfgang Gressmann, of the Norwegian Refugee Council, warned. “We must insist that civilians fleeing have genuinely safe exit routes out of the city.”

The agency said at least 1.2 million people were thought to be trapped inside Mosul and some 700,000 “might soon require humanitarian assistance”.