Turkey and Syrian Kurdish forces are both accusing each other of violating a temporary ceasefire agreement in northern Syria.
The US announced on Thursday it had brokered a five-day pause in fighting to allow Kurdish forces to withdraw.
Turkey views the Kurdish forces as terrorist groups and wants to create a "safe zone" buffer by its border.
Despite the ceasefire, some sporadic violence has continued – particularly around the border town of Ras-al-Ain.
On Saturday, Turkish President Recep Tayyip Erdogan vowed that Turkey would "crush the heads" of Kurdish fighters if they did not withdraw from the safe zone area in the 120-hour period agreed under the ceasefire.
Turkey's defence ministry accused Kurdish forces of carrying out 14 "provocative" attacks in the last 36 hours, mostly in the town, but insisted Turkish forces were fully abiding by the agreement.
However, the Kurdish-led Syrian Democratic Forces (SDF) have accused Turkey of violating the ceasefire.
They also accuse Turkish troops of failing to create a safe corridor for the evacuation of civilians and wounded people from the besieged town.
On Saturday the SDF urged US Vice-President Mike Pence, who helped broker the ceasefire, to pressure Turkey to allow the passage of civilians.
"Despite the constant communication with the American side and the promise made by them to solve this problem, there has not been any tangible progress in this regard," the SDF said in a statement.
The UK-based Syrian Observatory for Human Rights (SOHR) allege that deliveries of humanitarian aid have also been prevented from entering Ras-al-Ain.
The war monitor said Friday that the civilian death toll from the Turkish operation had now risen to 86.
Between 160,000 and 300,000 people have reportedly fled their homes since the offensive started ten days ago.
What prompted the offensive?
Turkish forces first launched their assault on 9 October, following an announcement US troops would withdraw from the Syria-Turkey border region.
President Erdogan's operation aims to push Kurdish fighters away from northernmost Syria and create a 20 mile (32km) safe zone for resettling up to two million Syrian refugees currently in Turkey.
The goal was to push back a Kurdish militia group – the People's Protection Units (YPG) – that Turkey views as a terrorist organisation.
Turkey had hoped to resettle up to two million Syrian refugees in the border area, but critics warned that could trigger ethnic cleansing of the local Kurdish population.
Since the offensive was launched, President Donald Trump has been accused by some, including senior Republicans, of abandoning a US ally. The SDF – a group dominated by the YPG – fought alongside the US against the Islamic State (IS) group in Syria.
There has been growing international concern about possible war crimes committed by Turkey and allied militias during the offensive.
Amnesty International says it has gathered "damning evidence" of war crimes and other violations by their side and the United Nations has called on Turkey to investigate the allegations.
Unconfirmed reports have also emerged that Turkish-allied forces have used white phosphorus, a chemical weapon which causes bad burns, in Syria.
The Organisation for the Prohibition of Chemical Weapons (OPCW) said it was aware of the claims and Read More – Source