Turkish troops have clashed with pro-Kurdish militiamen for the first time since Ankara sent tanks across the border, a monitor group said. Previously, the rebels accused Turkey of bombing civilians in the area.
Pro-Kurdish troops were fighting the Turkish army after it moved deeper into the Kurdish region in Syria, sources on the ground confirmed on Saturday.
"It's the first such case since Turkish tanks entered into Syrian territory on Wednesday," said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights.
Rahman added local fighters were Arabs who are allied with the Kurds.
The fighting also saw the first fatality of a Turkish soldier in Syria, according state media. One soldier was killed and three wounded by what Ankara said was a Kurdish rocket attack in the city of Jarablus.
In another incident on Saturday, Kurdish militants launched a rocket-propelled grenade at a Turkish airport in the southeastern city of Diyarbakir. There were no reports of casualties.
Kurds dominate the powerful Syrian Democratic Forces (SDF) faction. The SDF has been fighting the "Islamic State" (IS) militia in Syria, aided by US air power.
However, Ankara fears that SDF's territorial gains will boost Kurdish efforts to create an independent state on Turkey's doorstep. The Turkish "Euphrates Shield" operation aims to drive pro-Kurd forces out of the border area and across the Euphrates.
Earlier on Saturday, a military council linked to the SDF said that Turkish forces attacked the village of Amarna, causing civilian casualties. Pro-Kurdish officials described the attack as "a dangerous escalation that threatens the fate of the region."
"With this aggression, a new conflict period will begin," they said.
The officials also claimed Turkey was attacking "our forces that are fighting against [the] "Islamic State" group."
'Limited' support for Kurds
Many foreigners fear that the Turkish cross-border offensive might grow into an all-out war between SDF and Turkey, who are both allied with the US. Washington, however, appeared to back the NATO member, calling for Kurdish units to withdraw from the border region.
Late on Friday, US Secretary of State John Kerry said Washington had supported Kurdish fighters on a "limited basis" and that American officials remain in close coordination with Turkey.
"We are for a united Syria. We do not support an independent Kurd initiative," Kerry said.
rs, dj/jlw,kl (Reuters, AFP, AP)