BAGHDAD — Thousands of civilians are fleeing Fallujah after the city was declared liberated from the Islamic State, the United Nations said, while an Iraqi commander reported fierce clashes as elite counterterrorism forces pushed to clear out the remaining militants.
Islamic State fighters launched missiles, detonated a suicide car bomb, and deployed snipers against Iraqi forces, Brigadier General Haider al-Obeidi said. ‘‘Iraqi forces are still advancing despite the strong clashes,’’ he said.
Over the past three days, the UN says that nearly 10,000 families have fled Fallujah amid the heavy fighting. More than 80,000 civilians have fled Fallujah and its surrounding areas since the operation to retake the city from the Islamic State was announced last month, according to the UN.
‘‘Agencies are scrambling to respond to the rapidly evolving situation and we are bracing ourselves for another large exodus in the next few days as we estimate that thousands more people remain trapped in Fallujah,’’ said Bruno Geddo, the representative for the UN’s refugee agency in Iraq.
Prime Minister Haider al-Abadi declared victory for Iraq on Friday after special forces recaptured most of the city after weeks of fighting. This leaves Mosul, Iraq’s second-largest city, as the only remaining urban stronghold for Islamic State militants in the country.
The Norwegian Refugee Council said the civilian exodus has overwhelmed camps run by the Iraqi government and humanitarian groups, leaving thousands without shelter or proper sanitation.
“There are thousands without any tents, without any shelter, they have slept overnight out in the open,’’ said Karl Schembri with the Norwegian Refugee Council, an international humanitarian group.
The conflict that erupted in Iraq after the Islamic State blitzed across the country in the summer of 2014 has forced more than 3.4 million people to flee their homes.
In Syria on Sunday, government forces advanced to within 6 miles of the Islamic State-occupied Tabqa air base in the northern part of the country, part of a push to try to unseat the extremist group from its de facto capital, Raqqa.
Government forces recaptured the nearby Thawra oil field from Islamic State militants.
Activists said Sunday’s assault was accompanied by an aerial campaign on the town of Tabqa.