Turkey will set up a dozen observation posts across north-east Syria, President Recep Tayyip Erdogan said on Friday, insisting that a planned "safe zone" will extend much further than US officials said was covered under a fragile ceasefire deal.
Less than 24 hours after he agreed the five-day truce to allow Kurdish forces time to pull back from Turkey's military incursion, Mr Erdogan underlined Ankara's continued ambition to establish a presence along 300 miles of territory inside Syria.
On the border itself shelling could be heard near the Syrian town of Ras Al Ain on Friday morning despite Thursday's deal, and a spokesman for the Kurdish-led forces said Turkey was violating the truce, hitting civilian targets in the town.
Kurdish authorities in north-east Syria also accused Turkey of resorting to banned weapons such as napalm and white phosphorus munitions, a charge Mr Erdogan denied.
"There are certainly no chemical weapons in the inventory of our armed forces. This is all slander against our armed forces," he added.
But UN chemical weapons authorities said they were investigating the alleged use of white phosphorus by Turkish-backed forces.
The Organisation for the Prohibition of Chemical Weapons (OPCW) said it was "collecting information with regard to possible use of chemical weapons”.
Mr Erdogan warned he would resume a full-scale operation against Kurdish forces if they do not withdraw from the so-called "safe zone."
A US official said most of the fighting had stopped, although it would "take time for things to completely quiet down".
Donald Trump said on Friday he had spoken with Mr Erdogan who told him there had been some "minor" sniper and mortar fire in north-east Syria despite the truce, but that it had been quickly eliminated.
"He very much wants the ceasefire, or pause, to work," Mr Trump said in a post on Twitter. "Likewise, the Kurds want it, and the ultimate solution, to happen."
The United Nations Office for the Coordination of Humanitarian Affairs described the situation as “reportedly calm in most areas, with the exception of Ras Al Ain, where shelling and gunfire continued to be reported earlier today,” UN spokesman Stephane Dujarric told reporters in New York.
The truce, announced by US Vice President Mike Pence after talks in Ankara with Mr Erdogan, sets out a five-day pause to let the Kurdish-led SDF militia pull out of the Turkish "safe zone".
The deal was aimed at easing a crisis that saw Mr Trump order a hasty and unexpected US retreat, which his critics say amounted to abandoning loyal Kurdish allies that fought for years alongside US troops against ISIS.
On Friday, the heads of the foreign affairs committees of Germany, France, the UK and the European Parliament issued a joint statement condemning the Turkish offensive.
"We consider the intrusion as a military aggression and a violation of international law," the statement read.
"We consider the abandonment of the Syrian Kurds to be wrong," they said.
"The Syrian Democratic Forces, our partner in the Global Coalition, massively contributed to the successful yet unfinished fight against Da’esh (ISIS) in Syria and incurred heavy losses by doing so."
Turkey's incursion created a new humanitarian crisis in Syria with 200,000 civilians taking flight, according to Red Cross estimates. It also prompted a security alert over thousands of ISIS fighters held in Kurdish jails.
The joint statement warned that Turkey's military operation "may contribute to a resurgence" of terrorism and "undermines years of effort".
French president Emmanuel Macron on Friday decried Nato's inability to react to what he called Turkey's "crazy" offensive into northern Syria and said it was time Europe stopped acting like a junior ally when it came to the Middle East.
"I think that what has happened over the last days is a serious mistake by the West and Nato in the region."
Macron said that he, British Prime Minister Boris Johnson and German Chancellor Angela Merkel would meet Turkish President Tayyip Erdogan in the coming weeks.
Mr Trump has praised Thursday's deal, saying it would save "millions of lives". Turkey cast it as a victory in its campaign to control territory more than 30 km (around 20 miles) deep into Syria and drive out Kurdish fighters from the YPG, the SDF's main Kurdish component.
"As of now, the 120-hour period is on. In this 120-hour period, the terrorist organisation, the YPG, will leave the area we identified as a safe zone," Mr Erdogan told reporters after Friday prayers in Istanbul. The safe zone would be 32 km deep, and run "440 km from the very west to the east", he said.
But the US special envoy for Syria, James Jeffrey, said the accord covered a smaller area where Turkish forces and their Syrian rebel allies were fighting, between two border towns of Ras Al Ain and Tel Abyad, just 120 km away.
Speaking to journalists later on Friday, Mr Erdogan said Turkey plans to set up 12 observation posts in northeast Syria. A map of the region showed the planned posts stretching from the Iraq border in the east to the Euphrates river 300 miles to the west.
With the United States pulling its entire 1,000-strong military contingent from northern Syria, the extent of Turkey's ambitions is likely to be determined by Russia and Iran, filling the vacuum created by the US retreat.
The government of Syrian President Bashar Al Assad, backed by Moscow and Tehran, has already taken up positions in territory formerly protected by Washington, invited by the Kurds.
Mr Jeffrey acknowledged that Turkey was now negotiating with Moscow and Damascus over control of areas that Washington was vacating and were not covered by the US-Turkish truce pact.
"As you know we have a very convoluted situation now with Russian, Syrian army, Turkish, American, SDF and some Daesh (ISIS) elements all floating around in a very wild way," Mr Jeffrey said.
"Now, the Turks have their own discussions going on with the Russians and the Syrians in other areas of the northeast and in Manbij to the west of the Euphrates. Whether they incorporate that later into a Turkish-controlled safe zone, it was not discussed in any detail."
The joint US-Turkish statement released after Thursday's talks said Washington and Ankara would cooperate on handling ISIS fighters and family members held in prisons and camps - an important international concern.
Mr Pence said US sanctions imposed on Tuesday would be lifted once the ceasefire became permanent.
In Washington, US senators who have criticised the Trump administration for failing to prevent the Turkish assault in the first place said they would press ahead with legislation to impose sanctions against Turkey, a Nato ally.
The Turkish assault began after Mr Trump moved US troops out of the way following an October 6 phone call with the Turkish leader.
Turkey says the "safe zone" would make room to settle up to 2 million Syrian war refugees - roughly half the number it is currently hosting - and would push back the YPG militia, which Ankara deems a terrorist group due to its links to Kurdish insurgents in southeast Turkey.