Mortar fire by pro-Ankara forces Sunday killed a Myanmar national working as a cameraman and medic for a non-governmental group in northeast Syria, the group said.
Turkish troops and their Syrian proxies last month launched a cross-border attack against Kurdish fighters in northeastern Syria that has killed hundreds and caused tens of thousands to flee their homes.
A ceasefire signed by Moscow -- a key ally of Syria's government -- and Ankara on October 22 has mostly stemmed the fighting, but sporadic clashes persist.
The Free Burma Rangers (FBR) said one of its members from Myanmar, a country previously known as Burma, had been killed Sunday in a mortar strike by the Turkish army or their Syrian allies.
Our "cameraman and medic from Burma was killed today" north of the town of Tal Tamr, the group's head David Eubank said in a statement.
The mortar round "hit our forward casualty collection point where we were assembled to treat the wounded", the American veteran said.
An Iraqi member of the group was also wounded in the strike, he added.
The Syrian Observatory for Human Rights, a Britain-based monitor with sources inside Syria, said the attack happened in a village called Rashidiyya.
A spokesman for the Kurdish-led Syrian Democratic Forces said clashes were ongoing in surrounding areas.
"Fighting is ongoing in areas surrounding Tal Tamr," SDF spokesman Mustefa Bali told AFP.
The United States last month announced it was withdrawing forces from northern Syria, after years of relying on the Kurds to fight the Islamic State jihadist group.
Washington's move triggered a Turkish military offensive, and forced semi-autonomous Kurdish authorities to seek a rapprochement with the Damascus regime to fill the void left by the US.
Eubank established the FBR in Myanmar in 1997, with a slogan drawn from a Bible verse calling on people to "preach good news to the poor" and "release the oppressed".
Early this year, the group helped to ferry out thousands of people who streamed out of the last scrap of IS territory in Syria's far east, where the SDF defeated the jihadist group on the conventional battlefield.