Turkey's impending new offensive in northern Syria has raised fears of fresh war-crimes after videos of Turkish-backed militias executing unarmed civilians emerged online.

President Recep Tayyip Erdoğan launched Operation Peace Spring two weeks ago, after Donald Trump's announcement that the US would not stand in the way.

In the resulting chaos, as Turkish troops advanced much further into the supposed 'safe zone' in Syrian territory, shocking videos of fighters shooting defenseless prisoners emerged.

Four days after the offensive was launched on October 9, footage emerged showing the execution of nine apparently unarmed people on the M4 highway, Syria's main road.

Proxy militias filmed themselves executing restrained prisoners, while yelling 'God is great', and filmed the aftermath of the death of a prominent female Kurdish politician, Hevrin Khalaf.

In video of the executions on October 13 an armed man can be seen to be standing over Ms Khalaf, who numerous reports also claimed was raped and stoned before being killed.

Another fighter also filmed himself standing on her head after she had been killed.

The footage and images from the executions, first posted on a rebel group's page, quickly spread across the internet, causing outrage across the world and led to accusations of war crimes.

A 120-hour suspension of the fighting negotiated by the US is due to end tomorrow, after American troops have fully withdrawn from northern Syria.

Grabs from one of the videos shows a couple of the prisoners who were detained. Video appears to show a number of those captured being shot - despite the fact they were unarmed.

Members of the Turkish-backed militia can be seen pulling a number of the unarmed civilians from the car which has clearly been hit by a barrage of bullets

The prisoners can be seen forcefully being pushed to the ground and detained in grabs taken from a video that showed the Turkish-backed militia executing a number of prisoners

People with hands marked red to symbolise blood pose with the photo of Hevrin Khalaf, a politician and activist for women's rights who was reportedly killed on October 13 by Turkish-backed militias

American troops have been accused of abandoning their former allies to the Kurds to be ethnically cleansed by the Turkish forces.

And as the ceasefire draws to a close there are concerns for civilians who may be caught up in the bloodshed between the opposing forces.

The gruesome images of the October 13 execution have raised an outcry and led to the subsequent concerns that the offensive has paved the way to ethnic bloodletting and war crimes.

The footage which captured on camera phones and shows how the unarmed civilians were shot dead on the highway after pulled from their cars by the Turkish-backed militia.

This grab appears to show the driver being pulled from the vehicle before being executed by the militiamen on the side of the road in northern Syria

The people who were killed appeared to have been travelling along the M4 in this convoy when it was stopped and they were ordered to get out, before they were executed

In what human rights activists have described as clear evidence of war crimes the prisoners can be seen being pushed into a pile, kicked and herded by the armed men who shout insults at them before shooting them moments later.

Other footage online shows, Khalaf who had reportedly been stoned, before being executed, lying in the rubble.

Another video shows her driver being pulled from the car they had been in moments before also being killed.

Under the 1949 Geneva Convention attacks against civilians not taking direct part in the hostilities are deemed to be a serious violation of international law.

Execution: The militiamen filmed themselves executing this restrained prisoner while shouting abuse

Mourners attend the funerals of those who were killed in the roadside execution on October 13. The first casket contained the body of Hevrin Khalaf who had been working as the Secretary General of the Future Syria Party

Hours after news of the execution was made public there were reports of at least ten others travelling in a convoy were also killed in shelling by Turkish forces.

A number of those killed and injured were journalists, many working for foreign news agencies, when the convoy they were travelling in was struck as it arrived in Ras al-Ain (Sari Kani).

Members of Syrian, Kurdish and French news teams were reportedly among those caught up in the attack at the border town that advancing Turkish-allied forces have seized.

The Turkish-backed militias leading the offensive in Turkey are believed to be made up of Syrian Arabs who consider the Kurds long-time foes.

Turkey has demanded that Kurdish forces withdraw from a border strip 19 miles deep into Syrian territory.

It intends to use the new 'safe zone' to resettle refugees.

Speaking at a forum on Monday, Erdogan has criticised his allies for not the military action, which he considers to be a crucial battle against 'terrorists'.

'Turkey does not have an eye on any country's territory ... We consider such an accusation as the biggest insult directed to us,' he said at the event in his country's capital.

The Kurdish fighters belong to the YPG - an off offshoot of the outlawed Kurdistan Workers' Party (PKK), which has been waging a rebellion inside Turkey since 1984.

The PKK is blacklisted as a terror group by Ankara, the United States and the European Union.

A convoy of US vehicles is seen after withdrawing from northern Syria on October 21. The US has been criticised for the move which many say has paved the way to Turkey's incursion into Syria

Meanwhile, despite some promises it would consider keeping a small residual US military force to secure oil fields in eastern Syria, the US has continued its departure from northern Syria.

The US departure from the region is a move that has led to widespread international condemnation - none more so than from the locals who have been caught up in the bloody aftermath of the contentious political decision.

The Kurds were stunned when President Donald Trump two weeks ago abruptly decided to pull US troops out of border areas, abandoning their allied Kurdish-backed fighters ahead of Turkey's invasion.

Angry over the US withdrawal from Syria, residents of a Kurdish-dominated city pelted departing American military vehicles with potatoes as they drove through the border towns today

A video by the Kurdish news agency showed a convoy of armored vehicles driving through the northeastern city of Qamishli. People in the street hurled potatoes at the vehicles, shouting, 'No America,' and 'America liar,' in English.

'Like rats, America is running away,' one man shouted in Arabic. Another shouted obscenities and talked of babies in Kurdish-held areas who have died in the Turkish offensive.

The scenes encapsulated the Kurds' feelings of betrayal and added a new indignity to an American withdrawal that has been rushed and saw several close brushes with Turkish-backed forces.

At another location, near the town of Tal Tamr, a group of protesters raised banners to departing US troops late Sunday, according to an Associated Press video.

One man blocked the way of a US van with a poster reading: 'Thanks for US people, but Trump betrayed us.'

The Kurdish-led force was a key ally of the United States in the long and bloody fight that eventually brought down the Islamic State group's rule over northeast and eastern Syria.

Displaced Kurds can be seen waiting to cross to the Iraqi side of the border in northeastern Syria. Thousands have been displaced since Turkey launched its offensive into the region on October 9

A senior Kurdish official, Redur Khalil, said Monday his forces are complying with agreement and are preparing to complete the withdrawal.

He called for an international mechanism to protect Kurdish civilians who want to stay in their towns after Kurdish-led fighters leave.

Most Kurdish civilians have fled Ras al-Ayn, fearing killings or repression by Turkish-backed forces, and any still in the territory that the Kurdish fighters are leaving are likely to do the same.

More than 176,000 people have been driven from their homes in the violence.

About 70,000 of those are children, the international aid group Save the Children said Monday.

It said thousands are taking refuge in schools and abandoned buildings without electricity or in open fields in Kurdish-run areas around northeast Syria.

'Thousands of children and their families have once again had to leave everything they own to flee conflict and take shelter in unhygienic conditions without the basic necessities,' said Sonia Khush, Save the Children's Syria Response Director.