The “operation to clear the last remaining pocket of ISIS has just started”, Mustefa Bali, the spokesman of the United States-backed Syrian Democratic Forces (SDF), said in a statement on Friday.
SDF fighters have been trying to seize control of the village of Baghouz, near the Iraqi border, for several weeks.
The SDF said it extracted several hundred civilians from Baghouz late on Thursday.
“Many foreigners from various nationalities were among them,” Bali told the AFP news agency without specifying which ones.
The United Nations said in last week alone about 13,000 people have arrived at the Al-Hol camp in northeastern Syria after fleeing the ISIL.
“Many of the arrivals are exhausted, hungry and sick,” said Jens Laerke, spokesman of the UN Office for the Coordination of Humanitarian Affairs (OCHA), at a news briefing in Geneva.
The ISIL group, which once controlled large areas of Syria and Iraq, now holds about half a square kilometre of land along the Euphrates River.
A few hundred ISIL fighters are holed up there with their family members and other civilians who are among the group’s most determined supporters, many of whom travelled to Syria from all over the world.
Countries have been wrestling over whether to allow civilians who voluntarily joined ISIL to return to countries they had left. Some are women who gave birth while married to the ISIL fighters.
The SDF released a video on Thursday that said it would announce “a complete victory” over ISIL in about a week.
US President Donald Trump falsely claimed on Thursday that ISIL has lost 100 percent of the territory it once controlled in Syria.
In Moscow, the Russian military said the Syrian government was sending convoys to evacuate a refugee camp in southern Syria where tens of thousands of people suffer from lack of food and medical supplies.
Col Gen Mikhail Mizintsev said the Syrian convoys were heading on Friday to the Rukban camp and urged the US military in the area to secure their safe passage. Russia has accused the US of failing to provide humane conditions in the camp, which is home to about 40,000 people.
Mizintsev said the US military would bear “full responsibility for the safe passage” of convoys through its zone of control.
The Russian military said it will work together with the Syrian army to escort the convoys as they head to temporary accommodation centres for refugees established in several Syrian provinces.