Al-Qaeda leader urges 'co-operation' with IS against mutual enemies

Al-Qaeda chief Ayman al-Zawahiri has called for cooperation between al-Qaeda and the Islamic State (IS) despite continuing to regard the latter as illegitimate.

Zawahiri, who has previously criticised IS actions in Iraq and Syria, made the call in the first of a new video series called “Islamic Spring” attacking Shia, secularists and “crusaders”, referring to the US-led coalition currently carrying out airstrikes in Iraq and Syria.

"Despite the big mistakes [of IS], if I were in Iraq or Syria I would co-operate with them in killing the crusaders and secularists and Shi'ites even though I don't recognise the legitimacy of their state, because the matter is bigger than that,” he said.

He added, however, that “we don’t recognise this caliphate”.

IS has it roots in al-Qaeda in Iraq (AQI) formed in Iraq following the 2003 US-led invasion by Abu Musab al-Zarqawi.

However, following the group’s growth into IS and the emergence of the splinter group Al-Nusra Front, IS broke away from Zawahiri and proclaimed its own caliphate under Abu Bakr al-Baghdadi.

In spite of the split with Zawahiri, IS literature still venerates Zarqawi and al-Qaeda founder Osama Bin Laden.

Al-Nusra and IS have frequently clashed in Syria, along with other opposition forces, though there have been reports of local alliances in certain areas.

In November 2014, in response to the beginning of bombing raids in Syria by the US-led coalition - which have targeted both IS and Al-Nusra - members of IS and Al-Nusra, along with other hardline rebel factions, agreed to a detente.

The move also stands in contrast to a call by former CIA director David Petraeus for Al-Nusra to be armed as a bulwark againt IS in Syria.