Elite Iraqi security forces dislodged Islamic State militants from the main government building in Mosul on Tuesday, their last major city stronghold in Iraq, an Iraqi spokesman said.

A special Rapid Response team stormed the Nineveh governorate building and the surrounding government complex in an overnight operation, Lt. Col. Abdel Amir al-Mohammadawi, a spokesman for the elite interior ministry unit, told Reuters.

“They killed tens from Daesh,” he said, referring to the Islamic State group by one of its Arabic acronyms.

Recapturing the site would help Iraqi forces attack the militants in the nearby old city center and mark a symbolic step toward restoring state authority over Mosul, even though the buildings are destroyed and not being used by Islamic State.

Earlier on Monday, the Iraqi forces captured the second of Mosul’s five bridges. All of Mosul’s five bridges have been destroyed, but the capture of the remaining parts on the west bank of the Tigris facilitates the movement of forces progressing up the river, which cuts Mosul in two.

The bridge seized, Hurriya, is the second after one located farther south. Its capture shielded the back of the forces advancing toward a nearby complex of government buildings.

Rapid-response and federal police units on Monday took the court of justice and the Nineveh province police directorate buildings, neither of which were used by the Islamic State.

Recapturing the area would help Iraqi forces attack the militants in the old city and mark a symbolic step toward restoring state authority over Mosul.

The battle for Mosul, which started in mid-October, will enter a more complicated phase in the densely populated old city, where, the Iraqi military believes, several thousand militants are among the remaining civilian population. Aid agencies estimated that 750,000 civilians remained at the start of the latest offensive.

Iraqi forces captured the eastern side of Mosul in January after 100 days of fighting and launched their attack on the districts west of the Tigris last month.

The militants have barricaded streets with civilian vehicles and rigged them with explosives to hinder the advance of Iraqi forces, who were also met with sniper, machine-gun and mortar fire, as well as explosives dropped from drones.

Lined up against the militants in Mosul is a 100,000-strong force of Iraqi troops, Kurdish peshmerga fighters and Iranian-trained Shiite paramilitary groups.

More than 40,000 people have fled their homes in the past week, bringing the total number of displaced since the start of the offensive to nearly 210,000, according to the United Nations.