BEIRUT (Reuters) - The Kurdish-led Syrian Democratic Forces accused Turkey-backed fighters of killing a Kurdish politician in an ambush on a road in northern Syria on Saturday, drawing a denial from a Turkey-backed rebel force which said it had not advanced that far.

Turkey-backed Syrian rebel fighters stand near a truck mounted with a weapon, near the border town of Tel Abyad, Syria, October 12, 2019. REUTERS/Khalil Ashawi

The Syrian Observatory for Human Rights, a UK-based organization which reports on the war, said Turkey-backed groups had killed a total of nine civilians on the road, including Hervin Khalaf, secretary general of the Future Syria Party.

Khalaf had been returning from a meeting in Hasaka at the time of the attack in which her driver and an aide were also killed, said Hussein Omar, the Future Syria Party’s coordinator in Europe. Party officials including Khalaf have had contacts with U.S. officials since it was founded in 2018, he said.

Asked about the accusation that Turkey-backed groups had killed Khalaf, the spokesman for the Turkey-backed National Army, which groups Syrian rebel factions, said they had not made it as far as the highway known as the M4.

“I confirm to you that our forces have not reached the M4,” Youssef Hammoud said in a voice message to Reuters, saying that they had instead reached a road closer to the border.

Asked about the Observatory report that rebels had killed a total of nine civilians on the road, he gave the same answer.

Turkey and its Syrian rebel allies launched an offensive into SDF-held parts of northeastern Syria on Wednesday.

The SDF, in a statement, said Khalaf’s killing on the highway between Aleppo and Hasaka showed “the Turkish invasion does not differentiate between a soldier, a civilian or a politician”. The SDF statement identified her as party co-chair.

A map sent by an SDF official showed the location of the incident on the M4 highway southeast of Tel Abyad.

The SDF had earlier reported that a group of “mercenaries of the Turkish army” had killed a number of civilians on the road after infiltrating the area, without identifying them.

SDF forces had then repelled the attackers and the road was reopened, it said.

Led by an Arab from Manbij, Khalaf’s party was launched in a ceremony in Raqqa, the city captured by the SDF from Islamic State in 2017. Omar said it has been involved in the autonomous administration for northern Syria.

Omar said party officials including Khalaf, a civil engineer, had met U.S. officials on visits to the region. “The Americans have been in constant contact with this party up until now,” he told Reuters by phone.