A member of the Iraqi forces stands next to an armored vehicle in Mosul, April 16 2017.
The attack occurred in an area of western Mosul that has been recently liberated from the militants by US-backed Iraqi forces, AP reported on Saturday, citing an Iraqi military officer who spoke on condition of anonymity.
The assault on Mosul began in October 2016 with two special forces - the Counter-Terrorism Service and Rapid Response Division - advancing to the city's south, west and north before overrunning the eastern side earlier this year.
Using satellite imagery and local researches, the most recent evaluation confirms that western Mosul has undergone extensive destruction, "far greater than in the east", according to a senior United Nations aid official in the country.
Iraqi forces are in their sixth month of a push to retake Mosul from Islamic State.
USA -led military campaigns implemented against the Islamic State in the region have recently intensified however there have also been an increasing record of both friendly fire and civilian casualties.More news: Russia-Syria Ties to Dominate G7 Meeting of Foreign Ministers
The troops are trying to advance through the narrow streets in the old neighborhoods around the historical al-Nuri Mosque in the middle of Mosul's old city center, the source said.
Iraqi government forces, backed by US advisers, artillery and air support, have cleared the east and half of western Mosul and are now focused on the Old City.
Brigadier General Yahya Rasool said six soldiers suffered breathing problems from the attack on Sunday and were treated in a field clinic.
The war between Islamic State militants and Iraqi forces is taking a heavy toll on several hundred thousand civilians trapped inside the city, with severely malnourished babies reaching hospitals in government-held areas.
"People are suffering", said Mohammed Ahmed, a villager.