Turkish troops have reportedly bombarded a convoy of vehicles taking residents of the northern Syrian city of Raqqa to a border town, inflicting casualties among them.
The Kurdish Hawar news agency said the attack on the road leading to the border town of Tal Abyad killed three people and left several others injured.
The Britain-based Syrian Observatory for Human Rights said the Turkish air strike occurred when a convoy carrying a tribal leader reached the entrance of Tal Abyad. It said several people were injured but no-one was killed.
Turkish troops have been bombarding the town of Tal Abyad since the start of their ground offensive against Kurdish fighters on Wednesday.
Turkish President Recep Tayyip Erdogan has said 109 “terrorists” have been killed since the launch of the offensive.
He insists the action is needed to prevent the creation of a “terror state” along Turkey’s border with Syria.
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 Turkish border towns.
The governor’s office of Sanliurfa province said the baby was of Syrian nationality while the adult killed was Turkish. It said 46 people were injured in the rocket and mortar attacks.
At least five Turkish border towns have been hit by dozens of mortars since Wednesday.
A group of 14 international aid agencies has warned of an escalating humanitarian crisis in north-east Syria.
A statement co-signed by the organisations — including Doctors Without Borders, Oxfam and the Norwegian Refugee Council — said an estimated 450,000 people live within three miles of the Syria-Turkey border and “are at risk if all sides do not exercise maximum restraint and prioritise the protection of civilians”.
It added there are already more than 90,000 internally displaced people in the region, and tens of thousands of fighters with families are held in camps and detention centres.
The aid agencies are also urging all sides in the conflict to respect international humanitarian law and refrain from using explosive weapons in populated areas.
Mr Erdogan, meanwhile, has warned the EU not to call the operation an “invasion”, and renewed his threat to let Syrian refugees flood Europe.