Smoke rises from near the Syrian city of Ras al-Ain following an airstrike from Turkey (Picture: PA).
Turkish forces have reportedly hit a convoy of vehicles taking residents of the northern Syrian city of Raqqa town to a border town.
The Kurdish Hawar news agency said the attack happened on a road leading to the border town of Tal Abyad.
The Britain-based Syrian Observatory for Human Rights said the Turkish airstrike occurred when a convoy carrying a tribal leader reached the entrance of Tal Abyad.
Turkish troops have been targeting the town since the start of their ground offensive against Kurdish fighters on Wednesday.
Turkish President Recep Tayyip Erdogan said 109 "terrorists" had been killed since the offensive began.
He insisted the action is needed to prevent the creation of a "terror state" along Turkey's border with Syria.
Turkey, a NATO member, regards Kurdish fighters in the area as terrorists.
Meanwhile, Turkish officials say a nine-month-old baby and a civil servant were killed when mortars were fired from Kurdish-held northern Syria into Turkey's Sanliurfa province.
At least five Turkish border towns have been hit by dozens of mortars since Wednesday.
The violence comes after the withdrawal of US troops from north-eastern Syria, close to the border with Turkey.
American forces had been fighting alongside the Kurdish-led Syrian Democratic Force (SDF) against the so-called Islamic State (IS).
The US' decision to pull troops out of the area has received criticism.
A former SDF fighter labelled the decision a "betrayal", while a former US General said it raised concerns about America's "level of commitment" to its partners and allies.
The UK, France and Germany have all called for an emergency meeting of the United Nations Security Council to discuss the situation.
The Turkish offensive has also prompted concerns over the fate of captured IS fighters, held in prisons guarded by Kurdish forces.
The US says it has taken custody of two British detainees, notorious for their roles in an IS cell that tortured and killed nearly 30 Western hostages.
The two men, El Shafee Elsheikh and Alexanda Kotey, were part of a British cell nicknamed 'The Beatles' and have been removed from a prison run by the Kurdish-led militia.