U.S. aircraft continue to drop bombs on Ramadi as the Iraqi army moves through the city to clear out "little nests of fighters," a defense official said.
"We've killed … over 60 fighters inside of Ramadi just in the last 24 hours. So they are there," Army Col. Steve Warren, a U.S. Defense Department spokesman in Baghdad, said Wednesday.
More than a week after the Iraqi government declared victory in Ramadi, the Iraqi army continues to confront "squad-sized" Islamic State units in pockets of the city controlled by the extremist group, Warren said.
"What we see are small groups of enemy forces and in that group is maybe five to seven, maybe as many as a dozen, fighters in these groups … maybe centered around a machine gun or maybe centered around several rocket-propelled grenades," Warren said.
"But it's not a significant factor. We aren't seeing numbers of troops that are going to make any real difference," he said during a televised press briefing with Pentagon reporters.
Initially military officials thought there were up to 1,000 ISIS fighters in Ramadi, but that estimate dwindled to about 300 as the Iraqi army seized the city center. It's unclear how many remain there now, Warren said.
"Many are moving out. Some are probably trying to come in. There is all this motion; it's a little bit more difficult to get a good number on what's there," Warren said.
During the seven months that Islamic State militants controlled Ramadi, they dug a network of tunnels for moving around the city undetected.
"The enemy has extensively used tunnels. … This is why the Iraqi security forces have to be very deliberate and very methodical and very carefully move through these neighborhoods to clear them.
"There is still more work to be done," Warren said.
In the pockets of the city where the Shiite-led Iraqi army units have "cleared" out the ISIS fighters, they have begun to turn over the urban terrain to the Sunni forces who will hold it. "The tribal fighters have been moving into downtown Ramadi and taking over stabilization duties," Warren said.
Estimates on Iraq casualties suffered during the Ramadi operation are about 1,000 wounded and about 100 killed, Warren said.
In late December, Iraqi forces pushed into the city center, crossing a key canal with the help of a temporary bridge provided by the U.S. Army. They raised an Iraqi flag over Ramadi's government center Dec. 28.
U.S. and Iraqi officials say the bulk of the combat effort came from airstrikes provided by the U.S. and its allies.
The Iraqis' assault on the city marks the first major battlefield victory for that nation's forces since they collapsed in the face of an Islamic State group advance across northern Iraq in June 2014.
The operation did not involve support from ground-level U.S. combat advisers or attack helicopters. Top U.S. officials offered to provide that support in early December, but the Iraqi government declined.