Islamic State militants abducted about 2,000 civilians from Minbij shortly after they were forced to retreat from the strategic Syrian city near the Turkish border, Kurdish officials said Friday.
"We did not fire at [the militants] as they took civilians with them while fleeing towards Jarablous [in Aleppo]," Shervan Darwish, spokesman for the Kurdish Minbij Military Council, told dpa.
The Democratic Forces of Syria (DFS), a US-backed alliance of Kurds and Arabs, on Friday declared the "liberation" of Minbij near the Turkish border, from Islamic State forces after a campaign of more than two months against the extremist group.
Al-Sirib, the last area still under Islamic State control in Minbij, was "totally cleansed of the gangs," the DFS-linked Minbij Military Council said in a statement carried by the pro-Kurdish Firat news agency.
"Only mine-clearing operations are ongoing," it said.
US airstrikes had played a key role in the offensive, according to the statement.
Islamic State fighters withdrew from al-Sirib without a fight, heading to the area of Jarablous on the rural edge of northern Aleppo province, the Syrian Observatory for Human Rights said.
The DFS started a major offensive in late May, backed by a US-led air coalition, to retake Minbij, which has been under Islamic State control since 2014.
On August 6, the Britain-based Observatory reported that the DFS had taken almost full control of Minbij and started a mopping operation in the city's northern section, where Islamic State extremists were holed up.
The fall of Minbij, near the often porous border with Turkey, is likely to have a major impact on Islamic State's ability to bring supplies and fighters to its de facto Syrian capital of al-Raqqa and its remaining territories in Syria and Iraq.
Meanwhile, at least 12 people, among them five children, were killed late Friday in the northern countryside of Aleppo when planes raided the village of Hayan, the Britain-based Syrian Observatory for Human Rights.
It said the death toll is likely to increase as many of the wounded are in critical condition.
Fighting continued between rebels and regime forces in south-west Aleppo amid heavy strikes by Russian planes.
On Wednesday, Russia, a key ally of Syrian President Bashar al-Assad, said all military hostilities in Aleppo would halt for three hours a day for three consecutive days starting Thursday, to allow humanitarian convoys to deliver aid to civilians there.
The ceasefire had been due to begin at 10 am local time (0700 GMT).