An Iraqi forces tank advances towards the village of Salmani, south of Mosul, on October 30, 2016 during the ongoing battle against the Islamic State to liberate the city of Mosul
Qayyarah (Iraq) (AFP) - Iraqi forces said Sunday that they recaptured a series of villages surrounding jihadist-held Mosul as the operation to retake the city from the Islamic State group neared its third week.
Tens of thousands of Iraqi troops and Kurdish peshmerga fighters have been advancing on Mosul from the north, east and south after the launch on October 17 of a vast offensive to retake IS's last stronghold in the country.
After standing largely on the sidelines in the first days of the assault, forces from the Hashed al-Shaabi -- a paramilitary umbrella organisation dominated by Iran-backed Shiite militias -- began a push on Saturday towards the west of Mosul.
The ultimate aim is the recapture of Tal Afar, a town west of the city, and the severing of jihadist supply lines between Mosul and Syria.
In a series of statements on Sunday, the Hashed's media office announced it had retaken at least four villages southwest of Mosul.
Al-Imraini, one of the recaptured villages, is 45 kilometres (27 miles) from Tal Afar, according to the media office.
The drive toward Tal Afar could bring the fighting perilously close to the ancient city of Hatra, a UNESCO world heritage site, and the ruins of Nimrud -- two archaeological sites that have previously been vandalised by IS.
Forces from Iraq's autonomous Kurdish region also announced gains on Sunday, saying that they had recaptured six villages north and east of Mosul.
- Concerns over militias -
Kurdish units are effectively operating on the opposite side of Mosul from the Shiite militiamen, with whom relations are tense.
The involvement of Shiite militias in the Mosul operation has been a source of contention, though the Hashed's top commanders insist they do not plan to enter the largely Sunni city.
Iraqi Kurds and Sunni Arab politicians have opposed their involvement, as has Turkey which has a military presence east of Mosul despite repeated demands by Baghdad for the forces to be withdrawn.
Relations between the Hashed and the US-led coalition fighting IS are also tense, but the paramilitaries enjoy widespread support among members of Iraq's Shiite majority.
The Hashed has been a key force in Iraq's campaign to retake areas seized by IS in mid-2014, when the jihadists took control of large parts of Syria and Iraq and declared a cross-border "caliphate".
But the paramilitaries have been repeatedly accused of human rights violations during the war against IS, including summary killings, kidnappings and destruction of property.
Tal Afar was a Shiite-majority town of mostly ethnic Turkmens before the Sunni extremists of IS overran it in 2014, and its recapture is a main goal of Shiite militia forces.
In Qaraqosh, a Christian town east of Mosul that was recaptured from IS a few days before, a handful of the faithful gathered in a burnt out church on Sunday for the first mass held there in two years.
The bell tower was damaged, statues decapitated and missals strewn across the nave floor, which is still covered in soot from the fire the jihadists lit when they retreated.
- First mass after exile -
But some of the crosses have already been replaced and a new icon was laid on the main altar, where armed Christian militiamen took turns to light candles.
"After two years and three months in exile, I just celebrated the Eucharist in the cathedral of the Immaculate Conception the Islamic State wanted to destroy," said Yohanna Petros Mouche, the Syriac Catholic Archbishop of Mosul who led the mass.
The US-led coalition -- which has been assisting federal forces and Kurdish peshmerga with air strikes, training and advisers for two years -- said Friday that Iraqi forces were observing a pause in the two-week-old offensive.
In Bartalla, a Christian town just east of Mosul, army and counter-terrorism forces were consolidating their positions, unloading cases of weapons from trucks and organising ammunition stocks.
More than 17,600 people have fled their homes toward government-held areas since the Mosul operation began, the International Organization for Migration said on Sunday.
Numbers are expected to soar as Iraqi forces close in on the city, which is home to more than a million people.
The UN says there have been credible reports of IS carrying out mass executions in the city and seizing tens of thousands of people for use as human shields.
It cited reports indicating IS has forcibly taken civilians into Mosul, killing those who resist or who were previously members of Iraqi security forces.
It said more than 250 people were executed in just two days earlier this week.