A spokesman for the Syrian Democratic Forces on Sunday criticised US President Donald Trump's move to withdraw troops from northern Syria, saying Turkish forces driving millions of Kurds out of their homes was equal to ethnic cleaning.
Mustafa Bali, the spokesman in northern Syria, was responding to claims by Mr Trump and his Defence Secretary Mark Esper that the ceasefire with Turkey brokered by the US on Thursday was "holding up very nicely".
"Encouraging the ongoing genocide campaign is by far the greatest insult to our people so far," Mr Bali said in a tweet on Sunday evening.
"With all due respect, Mr President, what makes you think you have the right to drive millions of Kurds out of their homes and resettle them elsewhere? Isn’t this ethnic cleansing?"
On Sunday, The New York Times reported that Mr Trump was leaning in favour of a new Pentagon plan to keep a small contingent of troops in eastern Syria to counter ISIS and block the advance of the Syrian government into the region's oilfields.
The move would mark another U-turn in policy from the American president on Syria, who has previously committed to withdraw almost all US troops from the country.
Earlier on Sunday, Kurdish fighters belonging to the SDF withdrew from the besieged Syrian border town of Ras Al Ain, days after a US-brokered ceasefire deal was agreed to with Turkey.
Ankara launched a cross-border attack against Syria's Kurds on October 9 after the US announced a military pullout from the war-torn country's north-east.
Kino Gabriel, another SDF spokesman, said on Sunday that the group had no fighters left in the border town.
The evacuation is a boost to a ceasefire that has been shaky since it began on Thursday evening.
At least one soldier was killed on Sunday amid sporadic clashes with Kurdish fighters in northern Syria, the Turkish Defence Ministry said.
The ministry said on Sunday that Syrian Kurdish fighters have broken the three-day-old ceasefire about 20 times.
It said the soldier was killed during an observation shift earlier in the day, in an attack by anti-tank weapons and small arms fire, bringing Turkey's military death toll to seven soldiers.
The ministry also said it allowed a 39-vehicle humanitarian convoy to enter Ras Al Ain, a key border town that has seen some of the heaviest fighting. The convoy moved the wounded and others.
Dozens of fighters in military uniforms left on pickup trucks, passing checkpoints manned by Ankara-allied Syrian fighters.
The Syrian Observatory for Human Rights said the ambulances were carrying wounded civilians and fighters.
A pro-Turkey commander said that before the SDF announcement, the full withdrawal would "likely happen in waves" because there are "a large number" of SDF combatants still inside the town.
Turkey considers the Syrian Kurdish groups terrorists for their links to a decades-long Kurdish insurgency inside Turkey.
The soldier's death came on the same day that Turkish Foreign Minister Mevlut Cavusoglu said Ankara and Moscow would discuss the removal of the Syrian Kurdish YPG militia from the northern Syrian towns of Manbij and Kobani during talks in Sochi next week.
Turkish President Recep Tayyip Erdogan will travel to Sochi on Tuesday for emergency talks on Syria with Russian leader Vladimir Putin.
Mr Cavusoglu said Turkey expected the YPG to be removed from areas where the Syrian government, backed by Moscow, has sent troops in northern Syria.
He said Turkey did not want to see a single YPG fighter left in the "safe zone" at the end of the truce period.
Meanwhile, on Sunday evening, Germany's Foreign Minister Heiko Maas told German broadcaster ZDF that Turkey's offensive in northern Syria went against international law.
"If there is no basis in international law for such an invasion, then it can't be in accordance with international law," Mr Maas said in his strongest comments yet on the assault.
On Friday, the Kurdish militia accused Turkey of breaking the five-day pause by shelling civilian areas in the north-east and the border town of Ras Al Ain.
A senior Turkish official dismissed the accusations on Saturday, saying they were an attempt to sabotage the agreement between Ankara and Washington, and that Turkey fully supported the deal.
Mr Erdogan said on Saturday that the offensive would continue and Turkey would "crush the heads of terrorists" if the deal was not fully implemented.
Turkey has insisted that it is the duty of Washington to ensure the withdrawal of the YPG.
Turkey's Defence Ministry said late on Saturday that it was closely monitoring the withdrawal of the YPG and that it was in close contact with US officials over the issue and to provide logistical information.
Ankara aims to set up a "safe zone" about 32 kilometres into Syria.
Mr Erdogan said on Friday it would run for about 440km along the border, although the US special envoy for Syria said the accord covered a smaller area where Turkish forces and their Syrian rebel allies were fighting.
Mr Erdogan said on Friday that Turkey would set up a dozen observation posts across north-east Syria, and that he would hold talks with Mr Putin on what steps to take in the safe zone.
Another question is the arrangement for the rest of the north-eastern border, from the Euphrates River to Iraq border, most of which remains solely in the hands of Kurdish-led fighters.
US troops were once in much of that area, but President Donald Trump abruptly removed them, opening the way for the Turkish invasion.
Abandoned by their allies, the Kurds turned to Russia and secured an agreement for Syrian government forces to move into the north-east last week.
So far, the Syrian forces have only moved into one location directly on the border, the town of Kobani, and a few positions further south.