​Human Rights Watch (HRW) has condemned Turkey’s offensive on a Kurdish held area of northern Syria as causing unnecessary civilian casualties, as some counts put the toll as high as 120.

The statement on Friday cited three attacks in the contested canton of Afrin in late January that killed a total of 26 civilians, including 17 children.

The Turkish military had failed to take necessary precautions before carrying out the strikes and must conduct a thorough public investigation, the rights group said.

Explosions as Turkey confirms airstrikes on Afrin, Syria

“It appears that vulnerable civilians are facing displacement and death because of the way Turkey’s latest offensive is being conducted,” said Lama Fakih, the organisation’s deputy Middle East director.

“Turkey is obligated to take every feasible precaution to avoid harming or killing civilians, and to help them if they want to flee the violence.”

On Friday, Turkey’s President, Recep Tayyip Erdogan, said the army would be extending Operation Olive Branch, at the same time making every effort to avoid harming any civilians.

The Defence Minister, Nurettin Canikli, has previously dismissed reports of harmed civilians as false.

The air and ground offensive utilising Free Syrian Army fighters began on 20 January, opening a new front in Syria’s bloody seven-year-old conflict.

Turkish attack on Afrin, northern Syria – in pictures Show all 9 1 /9 Turkish attack on Afrin, northern Syria – in pictures Turkish attack on Afrin, northern Syria – in pictures Smoke billows following a Turkish airstrike on a village in the Afrin district, on 28 January, 2018. Turkey launched operation "Olive Branch" on January 20 against the Kurdish People's Protection Units (YPG) militia in Afrin, supporting Syrian opposition fighters with ground troops and air strikes AFP Turkish attack on Afrin, northern Syria – in pictures Smoke billows from surrounding villages during the Turkish military operation against the Kurdish enclave on 28 January, 2018 AFP/Getty Turkish attack on Afrin, northern Syria – in pictures Twenty-year old Kifah al-Moussa, a Syrian Arab woman living among the Kurds of Afrin province, was working on a chicken farm in the village of Maryameen when a Turkish aircraft bombed the building at midday on 21 January, wounding her in the chest. When she recovered consciousness, she found eight people from one family lying dead around her Yara Ismail Turkish attack on Afrin, northern Syria – in pictures Mohamed Hussein, a 58-year-old Kurdish farmer, lies in the Afrin hospital, wounded in the head and eye after his home was bombed by Turkish aircraft on the second night of the attack Yara Ismail Turkish attack on Afrin, northern Syria – in pictures Syrian Kurds sit on benches overlooking a street in Afrin, on 28 January, 2018. Above is a memorial to ‘martyrs’ who died in the fight against Isis AFP/Getty Turkish attack on Afrin, northern Syria – in pictures Smoke is seen rising on the Syrian side of the border, at Hassa, near Hatay, southern Turkey as Turkish jet fighters hit People's Protection Unit (YPG) positions, on 28 January, 2018 AFP/Getty Turkish attack on Afrin, northern Syria – in pictures A Turkish made T-155 Firtina (Storm) howitzer is dispatched to the border at Hassa near Hatay, southern Turkey, on 28 January, 2018 AFP/Getty Turkish attack on Afrin, northern Syria – in pictures A Turkish soldier waves a flag on Mount Barsaya, northeast of Afrin, on 28 January, 2018 Reuters Turkish attack on Afrin, northern Syria – in pictures Turkey-backed Free Syrian Army fighters are seen in Barsaya mountain, northeast of Afrin, on 28 January, 2018 Reuters

The attack is designed to clear out Kurdish YPG fighters – which Ankara sees as inextricably linked to the Turkey-based separatist PKK – from the border region.

It is widely believed to have been sparked by Turkish anger at renewed US support for the YPG and Arab-Kurdish Syrian Democratic Forces (SDF), which its Nato ally has backed as the most effective ground force against Isis.

The HRW statement comes a few days after paramilitary forces loyal to the government of Syrian President Bashar al Assad arrived in the area from Aleppo to support the Kurdish troops.

The two sides have at times been in direct conflict and at others have formed realpolitik alliances during Syria’s war.

In protests against the Turkish offensive across Kurdish areas of Syria on Thursday, demonstrators waved posters of Kurdish political leader Abdullah Ocalan and Mr Assad side by side.

The alliance has worried observers of the war, who fear it could trigger a complicated escalation in fighting.

Also on Friday, Turkey said it had shelled a YPG weapons convoy in Afrin, which Kurdish officials immediately claimed was a 40-strong chain of civilian vehicles also carrying food and medicine to areas affected by fighting.

The attack killed at least one person and injured 10, YPG spokesperson Birusk Hasaka said.