A top regional Trump envoy has said the US is "deeply concerned" after major new Israeli airstrikes on Syria overnight, following months of an absence of such attacks, and in the context of the broader Iran conflict.

The Syrian government and US Envoy to Iraq and Syria Tom Barrack said the attacks hit Abu al-Duhur military airfield in Idlib province in northwestern Syria. Barrack blasted it as an unnecessary escalation that threatens regional stability.