In a video issued to mark the anniversary of the September 11 2001 terror attacks, al-Qaeda accused Tehran on Monday of collaborating in a “crusader” war conducted by the west against Islam.

Ayman al-Zawahiri, the terrorist group’s deputy leader, hit out at Ayatollah Ali Khamenei, Iran’s supreme leader, on the tape, sections of which were aired by the broadcaster al-Jazeera.