The Sunni insurgency that is storming Iraq towards the capital Baghdad reportedly includes Baathist military officers from the era of Saddam Hussein's regime.

A former top military commander and vice president in the Hussein government, Izzat Ibrahim al-Douri, has joined forces with the jihadists of the Isis (The Islamic State of Iraq and the Levant) with the aim of overthrowing the Shiite-majority government of prime minister Nouri al-Maliki.

A senior Baathist leader told the New York Times that the groups are "unified by the same goal, which is getting rid of this sectarian government, ending this corrupt army and negotiating to form a Sunni Region".

Al-Douri escaped capture from the US forces after the invasion that overthrew Hussein and gave the majority Shiite Muslims a prominent role in the new government. Over the last few years, he encouraged anti-government Sunni protesters to challenge the Maliki government and force him out.

Maliki, who is identified with Iraq's long-neglected Shia, has been accused of centralising power within his own circle and disenfranchise Sunnis out of political power. His increased authoritarian rule has fueled the Sunni insurgency, according to experts.

In 2013, al-Douri addressed the Sunnis saying: "The people of Iraq and all its nationalist and Islamic forces support you until the realisation of your just demands for the fall of the Safavid-Persian alliance".

Safavid refers to the dynasty that ruled Shiite Iran from the 16th to 18th centuries. Maliki has been criticising for edging closer to Iran, which has a strong influence over several Iraqi Shiite parties.

Maliki suggested that many soldiers just handed over their weapons to militants without fighting. Iraqi forces fled or surrendered to the remarkable advance of the Sunni militants, who seized the northern cities of Mosul and Tikrit. The jihadists' success reflects not only the spillover of the Sunni insurgency in Syria but also the inability of Iraq's Shiite-led government to fully include Sunnis in the country's political life.