Nearly 100 civilians have been killed in a two-month offensive by Turkey and allied rebels in northern Syria, a monitoring group said on Monday.
No comment could be immediately obtained from Turkish officials, but in the past Ankara has disputed accusations of civilian deaths in its campaign.
The "Euphrates Shield" operation was launched in northern Syria on August 24 to fight both the Islamic State jihadist group and a Kurdish militia that Ankara considers a "terrorist" group.
Since then, Turkish air strikes and shelling as part of the assault have killed 96 civilians, including 22 children, the Syrian Observatory for Human Rights said.
The Britain-based monitor said rebels involved in the assault were leading the fight on the ground with Turkey lending heavy firepower -- mostly air strikes and artillery fired from Turkish soil.
"Ninety-two of the civilians, mostly Kurds, were killed in areas controlled by the Islamic State group," said Observatory head Rami Abdel Rahman.
He said the remaining four were killed in areas held by the Syrian Democratic Forces, a Kurdish-Arab alliance of fighters dominated by the People's Protection Units (YPG).
Turkey views the YPG and the Kurdish Democratic Union Party (PYD) as linked to the outlawed Kurdistan Workers' Party, which has been staging an insurgency in Turkey since 1984.
The PKK is proscribed as a terrorist organisation by the United States and European Union.
The Observatory in late August reported at least 40 civilians had been killed in Turkish shelling and air strikes, while Turkey's state-run Anadolu reported the deaths of 25 Kurdish "terrorists."
Ankara's operation overran the IS stronghold of Jarabulus along the Turkish border on its first day, and went on to seize the symbolic town of Dabiq in mid-October.
The Turkish-backed fighters have already seized more than 1,000 square kilometres since the operation began, according to Anadolu.
President Recep Tayyip Erdogan has said he wants to push further south to create a 5,000-square-kilometre (1,900 square-mile) safe zone in Syria.
IS, which seized control of large parts of Syria and Iraq in mid-2014 and declared an Islamic "caliphate", has been dealt a series of military defeats this year and is now facing an assault on its key Iraqi stronghold Mosul.