MOSUL, Iraq, Jan. 8 (Xinhua) -- Iraqi security forces on Sunday recaptured new areas from the Islamic State (IS) militants in the city of Mosul, as the troops reached the eastern bank of Tigris River for the first time in northern Iraq, the Iraqi military said.

In the eastern front, the elite forces of Iraq's Counter-Terrorism Service (CTS) continued their progress in two routes; the first one was advancing to the fourth bridge on the Tigris River, which bisects the city, and capturing the eastern bank for the first time in the battles of Mosul, a statement by the Iraqi Joint Operations Command said.

The battles left some 40 militants killed and two car bombs destroyed, as well as destroying a vehicle carrying heavy machine gun, the statement said.

The second CTS route within the eastern front was advancing toward Baladiyah and Succar neighborhoods amid heavy clashes that resulted in seizing the southern parts of the two neighborhoods, killing 43 extremist militants and destroying a vehicle carrying heavy machine gun, the source said.

In the southeastern front, the Iraqi federal police and army soldiers continued their heavy street-to-street fighting against IS militants in the neighborhoods of al-Salam, Palestine, Domiez and Sumer, recapturing several buildings and killing some 25 militants, according to the statement.

In the northern front, the army soldiers backed by international aircraft fought sporadic clashes during clearing operation to many of the 168-building residential compound of Hadbaa, which were freed in the advance which occurred for the time on Friday in the northern edges of the eastern side of Mosul, the statement said, adding that the clashes left some 10 militants killed and three booby-trapped vehicles destroyed.

In southwest of Mosul, the federal police forces repelled an attack by dozens of IS militants on the troops positions at the village of al-Adhbah, killing 12 militants and destroying two vehicles carrying heavy machine gun, it said.

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 recent report that the military operations in Mosul, have pushed about 136,000 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.