Casualties are increasing as Turkey presses on with its cross-border offensive on Kurdish-held areas of northern Syria.
At least 11 civilians have died and dozens of fighters from the Kurdish-led SDF and pro-Turkish factions have been killed, reports say.
The first death of a Turkish soldier was confirmed by Turkey’s military.
Tens of thousands of people have fled their homes, amid growing international criticism of the offensive.
Turkey moved into northern Syria on Wednesday after the US President, Donald Trump, pulled American troops out of the area.
Analysts say the US withdrawal effectively gave Turkey the green light to begin its cross-border assault.
Much of the region has been outside the control of the Syrian government as a consequence of the civil war. It has been controlled by the Syrian Democratic Forces (SDF) since 2015.
The SDF have been key allies of the US in the battle against the Islamic State (IS) group but Turkey regards the Kurdish militias of the SDF as “terrorists” who support an anti-Turkish insurgency.
Turkey defended its offensive as a bid to create a “safe zone” free of Kurdish militias which could also house Syrian refugees.
One major concern for the international community is the fate of thousands of suspected IS prisoners, including many foreign nationals, being guarded by Kurdish-led forces in the region.
Republicans in the US House of Representatives on Tuesday announced plans to introduce a sanctions bill against Turkey.
What’s the latest on the fighting?
On Thursday, Turkish troops partly encircled the border towns of Ras al-Ain and Tal Abyad.
But while the Turkish military said its operation was going to plan, Kurdish sources and activists from the Syrian Observatory for Human Rights (SOHR) said the offensive had not made much progress.
Turkish warplanes have struck targets in both towns, and video footage has shown columns of smoke rising above them. Tal Abyad’s only public hospital has been forced to close.
The Kurdish Red Crescent said there had been 11 confirmed civilian deaths so far and 28 serious injuries, mostly in Ras al-Ain and another border town, Qamishli. Some are children.
At least five people, including a Syrian baby, were reportedly killed in Kurdish shelling of Turkish border towns.
The SOHR reported at least 29 deaths among the SDF and 17 from among pro-Turkish Syrian rebels, the Syrian National Army, as more than 10 villages fell into Turkish hands.
In a later report they said that seven members of pro-Turkish forces including a Turkish soldier had been killed as the SDF retook a village in Tal Abyad region.
Turkey’s military confirmed a soldier’s death, and said three others had been wounded.
Turkey’s Anadolu news agency said late on Thursday 228 Kurdish militants had been “neutralised” since the start of the operation.
What about displaced people?
A refugee crisis is developing. Some 64,000 people have already reportedly fled their homes, the International Rescue Committee aid organisation said.
Aid groups say as many as 450,000 could be forced to move.
According to aid workers on the ground, the vast majority of civilians have fled Tal Abyad and those who remain fear for their lives.
Meanwhile a statement by the UN refugee agency says the Turkish bombardment has affected key civilian infrastructure such as water pumping stations, dams, power stations and oil fields. Thousands of people could lose adequate access to clean water in Hasakeh region, it said.
Turkey wants to create a “safe zone” running for 480km (300 miles) along the Syrian side of the border but says it will not advance deeper than a planned 32km limit.