Scattered fighting flared in northern Syria on Friday despite a ceasefire deal as Turkish President Recep Tayyip Erdogan warned he would resume a full-scale operation against Kurdish forces if they do not withdraw from a border "safe zone."
US President Donald Trump said Erdogan told him there had been "minor sniper and mortar fire" in the region "that was quickly eliminated" and the Turkish leader assured him in a call that "he very much wants the ceasefire, or pause, to work."
Mustefa Bali, a spokesman for the Kurdish Syrian Democratic Forces (SDF), accused Turkey, however, of violating the ceasefire deal reached during a visit to Ankara on Thursday by US Vice President Mike Pence.
"Despite the agreement to halt the fighting, air and artillery attacks continue to target the positions of fighters, civilian settlements and the hospital" in the battleground border town of Ras al-Ain in northeastern Syria, he said.
A war monitor group said 14 civilians were killed by Turkish air strikes and mortar fire by its Syrian proxies.
The deal brokered by Pence was meant to provide a five-day pause for the evacuation of Kurdish fighters from a "safe zone" Turkey wants to control along its border with Syria. Ankara considers the Kurdish forces to be "terrorists" linked to Kurdish rebels inside Turkey.
"If the promises are kept until Tuesday evening, the safe zone issue will be resolved," Erdogan told reporters in Istanbul. "If it fails, the operation... will start the minute 120 hours are over."
The suspension of hostilities looked designed to help Turkey achieve its main territorial goals without fighting, but its Syrian proxies continued to clash with Kurdish fighters on Friday.
The 14 civilians were killed in Turkish air strikes and mortar fire by allied Syrian fighters in and around the village of Bab al-Kheir, the Syrian Observatory for Human Rights said.
The Britain-based war monitor said eight fighters of the SDF -- the de facto army of the embattled Kurdish autonomous region -- were killed in the strikes.
Despite reports of continued fighting, Trump said "there is good will on both sides & a really good chance for success."
- No enforcement by US troops -
Secretary of State Mike Pompeo, who accompanied Pence to Ankara, said in an interview with Politico published Friday that he was "confident" the violence would cease and a ceasefire would take hold.
"There's not perfect command and control," Pompeo said. "You always want it to happen faster, cleaner in a more straightforward way. But we have some additional reporting that's not public that suggests that we think the path is still clear to being successful."
Under the deal, Kurdish forces are required to withdraw from a border strip 32 kilometres (20 miles) deep, clearing the way for the "safe zone" sought by Turkey.
The Kurdish-led SDF had said they were ready to abide by the ceasefire in border territory between Ras al-Ain and Tal Abyad to the west.
Pentagon chief Mark Esper said Friday that US troops were continuing their "deliberate withdrawal" from northeast Syria.
"No US ground forces will participate in the enforcement of this safe zone, however, we will remain in communication with both Turkey and the SDF," Esper said.
A senior Pentagon official said US forces will carry out aerial reconnaissance of the safe zone with the goal of watching over prisons holding Islamic State fighters.
Thousands of IS fighters and their family members are held in Kurdish-run jails and camps across northern Syria.
The prospect of thousands of the world's most radical jihadists breaking out in the chaos caused by Turkey's invasion has caused widespread alarm.
Trump said Friday that "some" European countries, which he did not name, "are now willing, for the first time, to take the (captured IS) Fighters that came from their nations."
"This is good news, but should have been done after WE captured them," he said. "Anyway, big progress being made!!!!"
The Turkish offensive was sparked by Trump's abrupt announcement earlier this month that he was withdrawing US troops from Syria, a move which triggered fierce criticism from Democrats and also members of the president's own Republican Party.
- 'Complicated region' -
Kurdish forces have put up fierce resistance in Ras al-Ain, with a network of tunnels, berms and trenches that held off the Turkish onslaught for a week.
On Friday afternoon, an AFP correspondent on the Turkish side of the border saw a big column of black smoke rise from Ras al-Ain, though it was unclear what was burning.
The Turkish military and its Syrian proxies -- mostly Arab and Turkmen former rebels used as a ground force -- have so far seized around 120 kilometres (70 miles) of territory along the border.
More than 500 people have been killed on the two sides, including nearly 100 civilians, while around 300,000 have been displaced, according to the Observatory.
The SDF fought alongside US forces to defeat IS in Syria and Iraq, but Trump has argued that it was no longer the US role to ensure calm in the volatile area.
"It's a complicated region," Trump said Friday. "Sometimes you have to go through some pain to get a good solution."