Iraqi troops pushed toward Fallujah from the south Friday, May 27 aiming to completely surround the militant-held city, Iraq's elite counter-terrrorism forces said, according to the Associated Press.

The operation to retake the town from the extremist Islamic State group was officially announced late Sunday night.

"Our troops are now in the process of surrounding the city from all (sides)," said Lt. General Abdul-Wahab al-Saadi, the head of the counterterrorism forces' Fallujah operation. "By doing so, we will besiege the city of Fallujah in full. And then we will start storming city from several directions with new forces."

Fallujah is located 65 kilometers west of Baghdad.

Booby-trapped explosives and large numbers of civilians unable to escape are expected to complicate operations moving forward, al-Saadi said, according to AP.

The spiritual leader of Iraq's Shiites called on Iraqi forces battling to retake the city of Fallujah to protect civilians there. Grand Ayatollah Ali al-Sistani said that "saving innocent people from harm's way is the most important thing, even more so than targeting the enemy."

His comments were delivered at Friday prayers by his representative, Ahmed al-Safi, in the holy city of Karbala, AP says.

Rights groups have expressed concerns for the tens of thousands of civilians estimated to still be in the city, which has been in IS hands for more than two years.

In the capital, Baghdad, Iraqi security forces fired tear gas and live ammunition to disperse thousands of anti-government protesters gathered in the city's Tahrir roundabout. The protesters assembled despite calls earlier this week from Iraqi Prime Minister Haider al-Abadi to halt protests so the country's security forces could focus on the Fallujah operation.