Iran has sought to put a brave face on the sudden overthrow of its Syrian ally Bashar al-Assad, insisting it will continue to confront the US and Israel in the region even after evacuating thousands of its citizens during the rebel takeover of Damascus.

Ayatollah Ali Khamenei, Iran’s supreme leader, said on Wednesday in his first comments since the defeat of the regime in Syria that Iran’s “resistance front” of allies across the Middle East would “grow stronger under pressure” and “extend its reach over the entire region”.

But Tehran has also acknowledged evacuating its citizens from Syria in the face of the Islamist rebel advance. “Over 4,000 Iranian citizens have been flown back home from Syria aboard 10 Mahan Air flights in the past three days,” said government spokesperson Fatemeh Mohajerani, adding that the foreign ministry would ensure the evacuation of every last Iranian citizen.