The United Nations special envoy for Syria has condemned an intense wave of Israeli airstrikes as Israel said its forces were on the ground in Syria to protect the Druze minority sect following days of clashes with Syrian pro-government gunmen.

It was the second time in days that Israel intervened militarily in Syria amid a wave of sectarian violence there.

Sectarian violence has erupted again in Syria, raising fresh doubt on the ability of the new Islamist rulers to control armed factions and calm tensions.