By Saif Hameed and Ulf Laessing
BAGHDAD/BARTELLA, Iraq (Reuters) - Islamic State fighters retreating in the face of a seven-week Iraqi military assault on their Mosul stronghold have hit back in the last two days, exploiting cloudy skies which hampered U.S.-led air support and highlighting the fragile army gains.
In a series of counter-attacks since Friday night, the jihadist fighters struck elite Iraqi troops spearheading the offensive in eastern Mosul, and attacked security forces to the south and west of the city.
On Sunday two militants tried to attack army barracks in the western province of Anbar. Police and army sources said the attackers were killed before they reached the base.
Iraqi officials say they continue to gain ground against the militants who still hold about three-quarters of the country's largest northern city which is Islamic State's last major urban stronghold in Iraq.
One military source said the militants had taken back some ground, but predicted their gains would be short-lived. "We withdraw to avoid civilian losses and then regain control. They can't hold territory for long," the source said.
But the fierce resistance means the military's campaign is likely to stretch well into next year as it seeks to recapture a city where the jihadists are dug in among civilians and using a network of tunnels to launch waves of attacks.
This has prompted fears among residents and aid groups of a winter food, water and fuel supply crisis for the million residents still in Islamic State-held areas of the city, and calls to speed up operations.
"Daesh (Islamic State) still controls our neighborhood, and the Iraqi forces have not taken a single step forward in three weeks. We're in despair," said a resident in Mosul's southeastern district of Intisar, where the army's Ninth Armoured Division has struggled to make gains.
"My family and I have been sleeping under the concrete stairs in our house for a month now, afraid of the random bombardment between the Iraqi forces and the Daesh elements," he told Reuters by telephone.
The capture of Mosul, the largest city under control of Islamic State in both Iraq and Syria, is seen as crucial toward dismantling the caliphate which the militants declared over parts of the two countries in 2014.
Some 100,000 Iraqi government troops, Kurdish security forces and mainly Shi'ite militiamen are participating in the assault on Mosul that began on Oct. 17, with air and ground support from a U.S.-led international military coalition.
A Reuters reporter in Bartella, about 10 km (6 miles) east of Mosul, saw tanks and army trucks heading toward the city on Sunday. Mud caused by recent rains was hindering movement and there was less artillery fire than in recent days.
"For the past two days there was almost no fighting," said a man who gave his name as Suleiman, who had fled Mosul.
A spokesman for the Counter Terrorism Services (CTS) who have been leading the Iraqi army advance in Mosul denied any let-up in the overall campaign.
"The operation is continuing on all fronts - there's no halt on any front," spokesman Sabah al-Numani told Iraqi television.
Iraqi commanders say they have killed at least 1,000 Islamic State fighters. A government adviser estimated the jihadist group now had about 4,000 fighters in Mosul.
The military has not given figures for its own casualties. The United Nations said last week nearly 2,000 members of the Iraqi security forces were killed across Iraq in November - a figure which Iraq says was based on unverified reports.
The elite CTS units and the armored division have captured around half of the eastern side of Mosul, which is split down the center by the Tigris river.
A U.S.-led coalition has bombed four of the five bridges across the river, aiming to stem a flow of suicide car bombers from the west, targeting the army in the eastern neighborhoods.
Officers say Islamic State has deployed more than 650 car bombs since the campaign started on Oct. 17 but say the pace of attacks has fallen off.
The militants, who have dug in and prepared their defense since seizing Mosul in mid-2014, have also struck with volleys of mortar bombs and used a network of tunnels to target soldiers.
In the Intisar district, the tanks of the armored division deployed there have struggled to adapt to close-quarter urban warfare, and commanders have summoned infantry reinforcement, an officer told Reuters.
Commanders also hope to stretch Islamic State defenses more thinly, by opening new fronts inside the city.
The head of the police rapid response forces, stationed a few miles south of Mosul on the west bank of the Tigris, told Iraqi television on Saturday evening his units were awaiting orders to advance north toward the city.
First they must take control of the Islamic State-held village of Albu Saif, the last obstacle before reaching Mosul airport on the southern edge of the city.
A military statement said the army had captured on Sunday three villages near the town of Shirqat, further south from Mosul and close to the sites of two attacks on Friday night by Islamic State fighters which killed 12 people.
Police and army sources said eight policemen were killed in Shayala village, north of Shirqat in one of the Friday night raids. Four other members of the security forces were killed at the same time in the village of Naml, south of Shirqat.
The army on Sunday was advancing slowly on the east bank of the Tigris, across the river from Shirqat, toward the Islamic State-held town of Hawija, the sources said.
(Additional reporting by Ahmed Rasheed in Baghdad and Omar Fahmy in Cairo; Editing by Pravin Char)