NIMRUD, Iraq -- Iraqi special forces pushed deeper into the northern city of Mosul on Wednesday, backed by U.S.-led airstrikes but under attack by rockets and suicide bombers from the Islamic State of Iraq and Syria (ISIS).

Troops have established a foothold in the city’s east, and earlier in the day, drove northward into the Tahrir neighborhood, where families left their houses to flee the fighting. Troops came under intense ISIS fire there, and Iraqi special forces said a suicide car bomber from ISIS disabled an Abrams tank belonging to the Iraqi army.

Mortars from ISIS-held territory in Mosul killed a child and wounded five others, according to Rudaw TV, which ran footage of their evacuation by Iraqi troops.

Away from the front lines, Iraqi forces on Wednesday assessed the damage to the ancient site of Nimrud, a town some 19 miles southeast of Mosul. Iraqi troops entered Nimrud on Sunday in what was the most significant gain in several days for government forces.

Get Breaking News Delivered to Your Inbox

Maj. Gen. Dhiaa al-Saadi, the deputy commander of Iraqi ground forces who oversaw the operation, said ISIS has almost completely destroyed the town’s ancient Assyrian archaeological site.

As the operation to retake Mosul progresses, al-Saadi said he expects to find more ruined heritage.

“We have information that all of the archaeological sites inside Mosul have already been destroyed,” he said.

The late 1980s discovery of treasures in Nimrud’s royal tombs was one of the 20th century’s most significant archaeological finds. The government said the ISIS militants, who captured the site in June 2014, destroyed it the following year, using heavy military vehicles

In Mosul’s Tahrir neighborhood, mortars from ISIS-held territory killed a child and wounded at least three others trying to flee the fighting, who were evacuated by the troops.

Footage from Kurdish broadcaster Rudaw showed families carrying bloodied children -- a little girl, a teenage boy and an infant -- into a Humvee. As they were evacuated, the dazed infant lost consciousness. Rudaw later said a 3-year-old girl died in the attack while three other children were wounded.

Warplanes from the U.S.-led coalition roared overhead in support of the special forces’ advance, while plumes of smoke rose over the city.

Iraqi troops are converging from several fronts on Mosul, the country’s second largest city and the last major ISIS holdout in Iraq. The special forces have been the tip of the spear, driving the furthest into the city itself, but they are still fighting over neighborhoods on its eastern edges.

The offensive to drive ISIS out of Mosul began on Oct. 17. After swift initial gains into the suburbs, progress has slowed as troops move into more built-up areas, still home to more than 1 million civilians.

From their foot hold in the east, special forces have been advancing slowly over the past week to avoid casualties and civilian deaths as ISIS fighters emerge to attack from the dense urban landscape, often with armor-plated suicide car bombs.