Turkish air strikes and artillery attacks have killed at least 40 civilians, and wounded dozens more, according to a group monitoring the Syrian war.

The strikes took place on Sunday in northern Syria, where Turkey and allied Syrian rebels are fighting Kurdish-allied militias.

The Syrian Observatory for Human Rights said at least 20 civilians were killed and 50 had been wounded in Turkish artillery fire and air strikes in the village of Jeb el-Kussa, south of Jarabulus, an area controlled by militias allied to the Kurdish-backed Syrian Democratic Forces (SDF).

The observatory added that another 20 had been killed and 25 wounded in Turkish air strikes near the town of al-Amarneh, AFP reports.

It also said at least four Kurdish fighters had been killed and 15 injured in the attacks on both areas.

Anadolu, Turkey's official press agency said Turkish air strikes killed 25 Kurdish “terrorists” and destroyed five buildings used by the fighters in the Jarabulus area.

The Turkish military is “taking every precaution and showing maximum sensitivity to ensure that civilians living in the area are not harmed,” Anadolu reported.

It remains unclear whether the reports refer to the same incidents.

The attack comes after Turkey suffered its first loss of life since launching an operation in Syria to drive Isis and Kurdish rebel groups back from border regions, which is now in its fifth day.

The observatory said the bombardment targeted an area south of Jarabulus, a former Isis stronghold, which Turkish-led forces captured on the first day of the offensive, code named “Euphrates Shield”.

The operation started as an effort to push Isis out of the Syrian city of Jarabulus, but officials have been vocal about the twin aim to oust Kurdish militias the Government views as terrorists.

In pictures: Turkey launches operation in Syria Show all 9 1 /9 In pictures: Turkey launches operation in Syria In pictures: Turkey launches operation in Syria Turkish tanks driving to the Syrian-Turkish border town of Jarabulus yesterday AFP/Getty In pictures: Turkey launches operation in Syria Turkish-backed gather on the outskirts of Jarabulus, Syria, ahead of an offensive on 24 August 2016 Reuters In pictures: Turkey launches operation in Syria Turkish army tanks make their way towards the Syrian border town of Jarabulus, Syria August 24, 2016 Reuters In pictures: Turkey launches operation in Syria Turkish soldiers return from Syria to Turkey with tanks after a military operation at the Syrian border as part of their offensive against the Islamic State (IS) militant group in Syria, Karkamis district of Gaziantep, Turkey, 25 August 2016 EPA In pictures: Turkey launches operation in Syria Turkish army tanks and Turkey-backed Syrian opposition forces move toward the Syrian border as pictured from Karkamis, Turkey, AP In pictures: Turkey launches operation in Syria Turkish tanks on their way to the Turkish-Syria border during an operation against Isis on 24 August 2016 EPA In pictures: Turkey launches operation in Syria Syrian opposition fighters being transported during preparations to enter Jarabulus in Karkamis, Turkey, on 24 August 2016. EPA In pictures: Turkey launches operation in Syria An air strike hitting Isis-controlled territory near Jarabulus, near the Turkish border, on 24 August 2016. EPA In pictures: Turkey launches operation in Syria A Turkish army tank and an armoured vehicle stationed near the border with Syria. Turkish media reports say Turkish artillery has launched new strikes at Isis targets across the border AP

It is the first Turkish ground intervention in the Syrian conflict and targeted both Isis and Syrian-Kurdish rebels backed by the US.

ANHA, the news agency of the Kurdish semi-autonomous areas, said the town of Beir Khoussa, around nine miles south of Jarabulus, has “reportedly lost all its residents” following the bombardments on Sunday.

An SDF spokesman Shervan Darwish said the air strikes and shelling started overnight and continued into Sunday killing many civilians in the town and nearby areas.

He said the bombing also targeted al-Amarneh village and that 50 Turkish tanks had been involved in the offensive.

Syrian state news agency SANA reported that 20 civilians were killed and 50 wounded in Turkish artillery shelling and air strikes, calling it Turkish “encroachment” on Syrian sovereignty under the pretext of fighting Isis.

Various factions of the Turkey-backed Syrian rebels said on Sunday they had seized at least four villages and one town from Kurdish-led forces south of Jarabulus.

One of the villages to change control was al-Amarneh, where clashes erupted for the first time between Turkish forces backed by tanks and pro-Kurdish fighters on Saturday.

The coalition-supported SDF Jarabulus Military Council said air strikes struck homes and killed civilians in the town, calling it “a dangerous escalation that threatens the fate of the region.”