Iraqi security forces launch a rocket towards Islamic State militants during clashes at a frontline in Ali Rash village, southeast of Mosul, Iraq, November 3, 2016. (Reuters)
Iraqi special forces threw themselves back into battle Saturday after a first foray into Mosul was blunted by stiffer than expected resistance from militants defending the birthplace of their "caliphate".
While the elite Counter-Terrorism Service (CTS) fought the Islamic State group in the streets of Mosul, the army and federal police attacked one of the last sizeable towns on the more distant southern front.
The mass exodus feared by aid groups of some of the million-plus civilians still trapped in Mosul has yet to materialise but the number of people displaced by the battle has grown sharply in recent days.
"Our forces are now engaged in fierce fighting inside the neighbourhoods of east Mosul," CTS spokesman Sabah al-Noman said, adding that the "fighting is house to house."
In Bartalla, a town to the east that Iraqi forces have used as a base since retaking it in the early days of the nearly three-week-old offensive, ambulances returning from the front with wounded CTS fighters whizzed by on a regular basis.
CTS forces made their first real push into the streets of Mosul on Friday but were met by a deluge of bombs and gunfire, and eventually forced into a partial pullback after a few hours.
"We weren't expecting such resistance. They had blocked all the roads," said one officer. "There are large numbers of jihadists... It was preferable to pull back and devise a new plan."
The hitch in the CTS advance appeared to contradict reports that IS had moved its resources away from the east of Mosul to the west bank of the River Tigris.
The militant group had looked increasingly pragmatic when vastly outnumbered and outgunned in recent months, sometimes giving up emblematic bastions almost without a fight.
But some of the 3,000 to 5,000 militants estimated to be inside the city may have been galvanised by a rare message from their leader Abu Bakr al-Baghdadi on Thursday.
The militant supremo released an audio recording for the first time in almost a year urging his fighters not to retreat.
Federal forces on the southern front attacked Hamam al-Alil, one of the main towns between their staging base in Qayyarah and Mosul.
"Army and federal police forces are attacking the Hamam al-Alil (area) from three sides with the support of army aviation," Staff Lieutenant General Abdulamir Yarallah said in a statement released by Joint Operations Command.
Forces working their way up the Tigris Valley have had more distance to cover than those on other fronts since Iraq launched the operation to retake Mosul on October 17.
Their advance has been slowed by IS resistance in villages along the way, bombs planted by the jihadists and concerns for the safety of civilians that has in some cases prevented full use of their firepower.
While the corridors called for by aid groups to allow the safe passage of civilians have yet to materialise, the number of arrivals in the displacement camps dotting the area has increased markedly.
The ministry of displacement and migration said it had taken in 9,000 displaced people during the past two days.
It put the total number of Iraqis displaced into camps since the start of the operation at 29,539.
Relief organisations were fighting the clock to build up their shelter capacity ahead of the feared mass exodus from Mosul.
Despite complaints from Iraqi forces on the ground that the number of air strikes has been insufficient, the US-led coalition insists it is providing more intense and sustained air support than ever before in its two-year campaign against IS.
Brett McGurk, US President Barack Obama's envoy to the coalition, hailed the latest military developments in a message on social media.
"New advances on all axes. Ways to go, but ahead of schedule," he said.
US and other commanders have warned that the offensive could take weeks or months.
Iraqi Prime Minister Haider al-Abadi, who has visited the front lines several times since the offensive started, has vowed to rid the country of IS by the end of the year.
Retaking Mosul could effectively end the IS group's days as a land-holding force in Iraq and deal a death blow to the "caliphate" Baghdadi proclaimed in the city in June 2014.