Drone captures build-up of Iraqi forces near Mosul as army enters ISIS stronghold (VIDEO)

Iraqi Army units have for the first time managed to enter one of the districts of Islamic State stronghold Mosul, following a two-week military operation aimed at clearing areas surrounding the city and ousting the terrorists.

The Iraqi Army and allied militias backed by the US-led coalition entered the Karama district of Mosul on Monday, an Iraqi officer reported, according to Reuters. This marks the first significant achievement in the advance into the city.

“They have entered Mosul. They are fighting now in Hay [district] al-Karama,” General Wissam Araji of the US-trained Counter Terrorism Service said, according to Reuters.

The battle for Mosul is expected to take weeks or even months.

“The battle of Mosul will not be a picnic. We are prepared for the battle of Mosul even if it lasts for months,” said Hadi al-Amiri, the leader of the Badr Organization, the largest Shiite militia supporting Iraqi government forces, Reuters reported.

Dozens of Iraqi military vehicles nearing Mosul from the east can be seen in a Ruptly drone video, posted October 31.

The Iraqi Counter Terrorism Service was on its way to Gogjali, an industrial zone, located 1km east of Mosul, and could enter it later on Monday, an officer of the US-trained troops told Reuters.

While Iraqi troops advanced in the south, in the north of Mosul five villages were cleared of jihadists with the help of Kurdish Peshmerga fighters, military statements said.

Pro-Iranian Iraqi Shiite militias, which joined the operation on Saturday, are to cut the route between Mosul and Raqqa, the unofficial capital of Islamic State (IS, formerly ISIS/ISIL) in Syria.

The number of civilians – some 1.5 million people – still living in Mosul has raised concerns amid aid groups worried about their safety when intense fighting starts.

Hundreds of residents have already been executed or used as human shields by IS militants, according to reports cited by the UN.

Experts say the recapture of Iraq’s second-biggest city is expected to strike a heavy blow to the terrorist group.

READ MORE: Fall of ISIS in Mosul may push terrorists to launch attacks in Europe – German spy chief

Mosul, the self-proclaimed capital of Islamic State in Iraq, came under the control of terrorists back in 2014. The Iraqi Army, along with a number of local militias, started the offensive to retake the city on October 17. Some 30,000 soldiers and militiamen backed by the US-led international coalition are taking part in the advance.