Near Baghouz (Syria) (AFP) - Kurdish-led forces battled jihadists defending their last village on Saturday as operations were relaunched to flush out the Islamic State group from eastern Syria after several days of humanitarian evacuations.

The US-backed Syrian Democratic Forces pushed into Baghouz, a tiny hamlet near the Iraqi border where IS fighters have been making a desperate last stand.

An official for the Kurdish People's Protection Units (YPG), which forms the backbone of the SDF, on Saturday said they had breached the jihadists' perimeter.

"The assault is underway -- the forces have started to enter the last (IS) pocket," said Aram Kojeir, a YPG official on the ground.

"The advance on the ground is taking place on three axes," he said, adding that the SDF had also taken control of a hill overlooking the last redoubt.

AFP reporters near the front line could see thick black smoke rising above the heart of the village, which SDF units approached through outlying farms.

"The intense fighting continues," spokesman Adnan Afrin told reporters, adding that eight SDF fighters had been seriously wounded in the first few hours of the battle.

"It's closer combat now, the distance between us and the jihadists is gone," he said, explaining that a one-kilometre (half-mile) buffer had been maintained in recent days.

An AFP journalist near Baghouz saw military planes in the sky.

The SDF launched the assault late on Friday after a week-long exodus that saw thousands of people flee the enclave.

While IS fighters, who have been besieged for weeks in an ever-shrinking pocket, are vastly outgunned, their use of tunnels, booby-traps and suicide bombers is hampering the SDF advance.

- 'Surprises' -

"We can't put a timeframe on this battle -- two weeks, three weeks or a week -- it will depend on the surprises we get along the way," Afrin said.

"Those who have not surrendered by now will meet their fate there," he said.

Most of the more than 50,000 people who left the very last rump of the IS "caliphate" in recent weeks were women and children.

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Some of the evacuees, however, were suspected fighters either surrendering to the SDF or attempting to slip back into civilian life.

The jihadists are cornered in a bend of the Euphrates, with Syrian government forces and their allies on the west bank of the Euphrates blocking any escape across the river and Iraqi government forces blocking any move downstream.

The Syrian Observatory for Human Rights monitoring group said seven IS fighters were shot dead by Syrian government forces and allied Iranian militiamen.

Only a few dozen people were evacuated by the SDF on Friday in the smallest convoy in days, prompting the Kurdish-led force to close the humanitarian window and resume their offensive.

The assault will deal a final death blow to the "caliphate" which IS supremo Abu Bakr al-Baghdadi proclaimed in mid-2014 and which once covered territory larger than Britain.

At its peak, the proto-state covered large parts of Iraq and Syria, administered millions of people, minted its own currency, levied taxes and produced its own textbooks.

- Yazidis -

It effectively collapsed in 2017 when IS lost major cities such as Mosul in northern Iraq and Syria's Raqa following massive offensives by government armies and their respective international allies in both countries.

While the last remains of IS' statehood experiment are about to disappear, the group remains a potent force in both Syria and Iraq, where it carries out deadly attacks.

Its brutal legacy is still raw and the scope of the atrocities committed under its rule continues to emerge, even in areas where its fighters were defeated long ago.

The SDF this week announced that yet another mass grave was discovered, this time near Baghouz, and that the severed heads of women were found in it.

While the victims were not immediately identified, local fighters believe the executed women are likely to be members of the Yazidi minority.

Members of the mostly Iraq-based religious minority are considered heretics by IS, which tried to exterminate them in 2014.

Many of the thousands of women abducted and enslaved by IS in the early years of the "caliphate" are still missing today and it is feared some may be held captive in Baghouz.

Nadia Murad, the Nobel Peace Prize laureate and herself an Iraqi Yazidi who was kidnapped and raped, urged the US-led coalition backing the SDF to help secure their safe return.

"The Global Coalition to Defeat ISIS must have a plan to help rescue Yazidis that are still missing," she said in a statement Friday, using the Arabic acronym for IS.

Some Yazidis managed to slip out with the thousands of civilians evacuated over the past 10 days.