BAGHDAD — Iraqi forces gained control of the main hospital in Fallujah on Saturday and were clearing mines after driving the Islamic State group from most of the city, one of its last remaining strongholds in the Anbar province west of Baghdad, a military official said.

Fighting was still underway in parts of the city, where U.S. and Iraqi warplanes targeted snipers and other IS positions, Brig. Gen. Haider al-Obeidi told The Associated Press.

Troops had cautiously advanced toward the hospital, fearing that the militants would use patients as human shields, but when they stormed the facility they found no patients inside, he said, adding that the Iraqi flag has been raised over the building.

The troops are now pushing into the northern neighborhoods of Shurta and Golan, he said.

Iraqi special forces swept into Fallujah on Friday, recapturing most of the city after weeks of fighting on its outskirts. Al-Obeidi said Friday that Iraqi troops controlled 80 percent of the city, with Islamic State fighters concentrated in four districts on its northern edge.

Fallujah was the first Iraqi city to fall to the extremist group, also known as ISIS or ISIL, in January 2014, and was the last major ISIS foothold in the sprawling Anbar province, the heartland of the country’s Sunni minority. The group still controls Iraq’s second largest city, Mosul, in the north.

Iraqi troops have been advancing under the cover of airstrikes by the U.S.-led coalition and Iraq’s air force. The operation inside the city of Fallujah was being conducted by the Iraqi army, regional and federal police forces as well as special antiterrorism units. Shiite militias, known as the Popular Mobilization Force, remained outside Fallujah and have not taken part in the recent battles.

Aid groups estimated that 50,000 civilians were trapped inside Fallujah when the assault began several weeks ago, and that 30,000 to 42,000 of those have fled since then. The majority have been staying in camps near the city.

As government forces swept in on Friday, thousands of residents fled the city, some swimming across the Euphrates river to reach safety.

On Friday evening, Iraqi Prime Minister Haider al-Abadi spoke on national TV from the joint command center, congratulating the troops on their victories. “We promised to liberate Fallujah, and it has returned to the embrace of the nation,” he said.

The conflict in Iraq has forced more than 3.3 million people to flee their homes. Iraq is also hosting up to 300,000 refugees who have fled the civil war in neighboring Syria. Most are living in camps or informal settlements.

In the central province of Salahuddin, where ISIS suffered a major defeat last year when it lost former Iraqi leader Saddam Hussein’s hometown of Tikrit, government forces pushed north of the province toward ISIS territory, said Brig. Gen. Yahya Rasoul.

Rasoul said the fighting is concentrated north of the oil refinery of Beiji, Iraq’s largest. The refinery has not been working since ISIS seized much of northern and western Iraq in 2014, declaring a caliphate.

Despite being under attack on several fronts in Iraq and Syria, the extremists carried out a suicide truck bomb attack near the office of a Kurdish group in northern Iraq.

The blast killed at least one person, according to Shallal Abdoul, the mayor of the northern town of Tuz Khormato.