MOSUL, Iraq, Jan. 12 (Xinhua) -- Iraqi security forces on Thursday retook control of more areas in the eastern side of the Islamic State (IS) stronghold in Mosul in northern Iraq, as fierce clashes continued against the extremist militants, the Iraqi military said.
In the southeastern front, a rapid reaction force affiliated with the Iraqi federal police completely freed al-Salam neighborhood and raised the Iraqi flags on some of its buildings after heavy clashes with IS militants that left dozens of IS militants killed and wounded, a statement by the Iraqi Joint Operations Command said.
The federal police also freed the neighborhoods of Sumer and Sahiron after days of fierce street-to-street clashes in the southeastern part of the eastern side of the Tigris River that bisects Mosul, the statement said.
The troops killed a prominent IS leader and his aide during the battles Sumer neighborhood, according to Brigadier General Ali Mahmoud from the federal police who spoke to Xinhua by telephone.
In the eastern front, the elite forces of Iraq's Counter-Terrorism Service (CTS) have been fighting heavy clashes during the day with IS militants in Faisaliyah neighborhood, just near the old bridge that linked to downtown Mosul in western side of Tigris, a source from CTS told Xinhua on condition of anonymity.
The CTS commandos are also fighting to flush out IS militants from several neighborhoods, which were freed during the battles of the past two days, the source said.
"The terrorist Daesh (IS) militants are collapsing after losing most of the eastern side neighborhoods and after many of their leaders were killed by the security forces," the source added.
The battles in Mosul came as the CTS commandos, army troops and federal police launched on Dec. 29 the second phase of a major offensive to free Mosul.
The troops made their new push into several neighborhoods in the eastern side of Mosul, locally known as the left bank of the Tigris River.
Last month, battles in Mosul had been slowed as extremist militants used locals as human shields, resorted to suicide car bombs and made mortar and sniper attacks in stiff resistance.
The UN High Commissioner for Refugees (UNHCR) said in a report issued earlier in the day that the military operations in Mosul have pushed up to 145,000 civilians to flee their homes in the city and its adjacent districts since the beginning of military offensive in October to reclaim the IS largest stronghold in Iraq.
More than 1.5 million people were trapped in the city of roughly two million population previously. Cold winter worsened the conditions for the displaced people who suffered severe shortages of food and water, while camps and other emergency shelters reached maximum capacity.
Iraqi Prime Minister Haider al-Abadi on Oct. 17 announced a major offensive to retake Mosul, the country's second largest city.
Since then, Iraqi security forces, backed by international coalition forces, have inched to the eastern fringes of Mosul and made progress on other routes around the city.
Mosul, some 400 km north of the Iraqi capital of Baghdad, has been under IS control since June 2014, when Iraqi government forces abandoned their weapons and fled, enabling IS militants to take control of parts of Iraq's northern and western regions.