Dozens of civilians were killed in Turkish airstrikes on Kurdish-held areas in Syria on Sunday, as the West's two main allies in the conflict inched closer to full-blown war.

Some 35 people died in dawn raids on Jeb el-Kussa and Al-Amarneh, villages close to the Turkish border.

Ankara, which has the support of the US, claimed they were “terrorists” from outlawed Kurdish militias.

The Jarabulus Military Council, which is allied with the Kurdish-led Syrian Democratic Forces (SDF), said the strikes marked an "unprecedented and dangerous escalation".

Turkey also suffered its first casualty in Operation Euphrates Shield after an attack by Kurdish fighters left one soldier dead and three injured.