Smoke rises over Karama district in Mosul where Iraqi troops are fighting Islamic State, in this picture taken near Mosul, Iraq October 31, 2016. REUTERS/Stephen Kalin

EAST OF MOSUL, Iraq (Reuters) - Iraqi troops entered the Karama district of the Islamic State stronghold of Mosul on Monday, their first advance into the city itself after two weeks of fighting in the surrounding area to dislodge the militants, an officer said.

“They have entered Mosul,” General Wissam Araji of the U.S.-trained Counter Terrorism Service told Reuters. “They are fighting now in Hay (disrict) al-Karama.”

The counter-terrorism unit resumed the offensive on the eastern front on Monday. It had paused its advance last week after it made gains quicker than forces on other fronts, to allow them to close the gap and get nearer to the city.

Iraqi security forces and Kurdish Peshmerga fighters started the offensive on Oct. 17, with air and ground support from the U.S.-led coalition against the hardline Sunni group.

Pro-Iranian Iraqi Shi’ite militias joined the fighting on Saturday, aiming to cut the route between Mosul and Raqqa, Islamic State’s main stronghold in Syria.

The battle for Mosul, still home to 1.5 million residents, is shaping up to be one of the toughest in a decade of turmoil following the U.S-led invasion that toppled Saddam Hussein in 2003.

The CTS will hold its advance in Karama until the forces on the other fronts advance “to protect their back,” Araji said in Bazwaia, a village which was retaken from Islamic State earlier in the day, at the edge of the city’s eastern suburb.