The US-led coalition has acknowledged hitting an explosives-laden vehicle in a March 17 strike; the coalition said separately that a review of its airstrikes indicated one strike occurred that day in the area where the casualties were reported.
US officials have not confirmed the senior Iraqi officer's account. The US military is investigating, it said.
Bashar al Kiki, chairman of the Nineveh Provincial Council and the source of the death toll, backed off the figure Sunday, saying that 200 was the death toll from multiple locations, citing his sources. He did not provide further details.
The US-led coalition confirmed Saturday that it had carried out an airstrike on March 17
"at the location corresponding to allegations of civilian casualties."
Col. Muntathar Al-Shamari, the head of the Iraqi Counterterrorism Unit in Mosul, said that, prior to the airstrike, Iraqi counterterrorism forces had asked the US-led coalition to engage an ISIS vehicle that had been loaded with explosives.
"When the (vehicle) was struck, it exploded, destroying one or two of the houses next to where families were hiding," he said.
Al-Shamari characterized the report of 200 dead as an exaggeration.
Around 130 people were hiding in one of the homes, Iraqi Joint Military Command spokesman Brigadier General Yahya Rasool said.
82nd Airborne troops deploying
Earlier Sunday, the Iraqi military said 61 bodies had been pulled from the rubble at the site, adding that there was no sign the homes had been directly hit from the air. Of the 61 bodies recovered so far, it is unclear how many belong to civilians and how many might be ISIS fighters.
Abdullah Amr said he lives three or four houses down from the site of the explosion, which he said came in the early morning hours. One large dwelling housed 17 people from six different families, including the family of the homeowner who took them all in, he said.
Chaos erupted after the strike, he said, and as he and his family could hear people screaming, "I am alive! Save me!"
US and Iraqi forces have been making an all-out push to retake Mosul from ISIS since October. Iraq's second-largest city has been under the terrorist group's control since 2014. The city is ISIS' last major stronghold in the country.
Soldiers with the 82nd Airborne Division are deploying to help Iraqi forces recapture Mosul. The troops are "deploying to Iraq on a non-enduring temporary mission to provide 'advise and assist' support to our Iraq partners," an Operation Inherent Resolve spokesperson said.
A US defense official said the troops will number in the "low hundreds" and are likely to operate out of east Mosul and Qayyarah West Air Base, according to the official.
The defense departments from both Iraq and the United States launched investigations Saturday
into airstrikes between March 17 and 23 and the civilian deaths.
A coalition review of airstrikes during that period found only one that corresponded to reports of civilian casualties in Mosul. That was the one on March 17.
The Iraqi military said in a statement Sunday that the home it examined had been reduced to rubble, but there was no sign of it being hit from the air. The team found a vehicle bomb and detonator in the debris. Those findings, along with witness accounts, led the team to believe that ISIS fighters had blown up the home.
Twenty-five women and children were rescued from the location alive, the military said.
'Body parts sticking out of the rubble'
In several parts of western Mosul, civilians say they are being caught up in coalition airstrikes, as well as crossfire between the Iraqi forces and ISIS fighters, Reuters reports.
Los Angeles Times reporter Molly Hennessy-Fiske, who visited the area in question with a civil defense group Friday, told CNN that she saw at least 50 dead bodies, as well as body parts, sticking out of the rubble.
"Hands, feet -- there were some remains that were wrapped in blankets. Most of them that they had retrieved they put in body bags. And (the civil defense group) unzipped some of those because they wanted to show us that some of the victims were women, including at least one pregnant woman and children. Some babies as well," she said.
The area was crowded as, according to the Iraqis there, ISIS militants had forced them into the area, Hennessy-Fiske said. Residents she spoke to said ISIS had brought a truck with explosives to the area days before the strike and that its fighters were shooting at aircraft above them when an "explosion happened," she said.
"Some people I talked to said the building started falling down on them. Some saw that truck that was parked on the street explode. It wasn't clear why that was -- if it was triggered by the strike or not -- and some managed to escape unharmed."
The US Central Command said Saturday that it has opened a probe "to determine the facts surrounding this strike and the validity of the allegation of civilian casualties."
"Our goal has always been for zero civilian casualties," the statement said, "but the coalition will not abandon our commitment to our Iraqi partners because of ISIS' inhuman tactics terrorizing civilians, using human shields, and fighting from protected sites such as schools, hospitals, religious sites and civilian neighborhoods."
The US military is also investigating allegations
of civilian casualties during two recent airstrikes in Syria.
New tactics in western Mosul
Iraqi security forces said Saturday that new tactics would be needed in the battle to recapture western Mosul from ISIS in order to keep civilians out of harm's way.
Many of the roads in Mosul's old city are narrow, making targeted airstrikes challenging.
"We have reached the old city. It's more complicated warfare," according to Lt. Col. Abdul Amir Muhammadawi, spokesman for the rapid response teams. "The old city has old buildings and small alleyways, and to protect the civilians, we need new tactics."
Local and UN officials have said hundreds of thousands of civilians are trapped in areas under ISIS control in western Mosul. The United Nations also said it is "profoundly concerned" over reports "of a high number of civilian casualties" in the city's al Jadidah area.
There are about 600,000 civilians feared trapped in western Mosul, according to the International Organization of Migration. Iraqi forces have regained control of the city's east.
This month, Iraqi forces seized Mosul's main government building and central bank from ISIS militants and are now closing in on the historic Al Nuri mosque where ISIS leader Abu Bakr al Baghdadi first declared his envisioned Islamic caliphate.