The Iraqi government has accused Saudi Arabia of being ‘responsible’ for the insurgent attacks in the country and has blamed Riyadh for supporting ‘genocide’ in the country by backing Sunni militants.

“We hold them responsible for supporting these groups financially and morally, and for the outcome of that – which includes crimes that may qualify as genocide: the spilling of Iraqi blood, the destruction of Iraqi state institutions and historic and religious sites,” the Shia-led cabinet said in a statement.

Saudi Arabia has denied backing fighters from the Islamic State in Iraq and Syria (Isis) and has instead blamed sectarianism for the violence in Iraq.

The country has been rocked by the sudden and rapid siege by Isis, which has in the last week taken control of large areas of northern Iraq including the cities of Mosul and Tikrit.

Isis claims to have massacred 1,700 Iraqi soldiers in northern Iraq during the siege. Caretaker Prime Minister Nouri al-Maliki has said he plans to launch a counter-offensive from the city of Samarra, 125 kilometres north of Baghdad and has urged people to take up arms and defend the country against the insurgents.

Al-Maliki’s Shia-dominated government has left many Sunnis in western and northern Iraq feeling marginalised from power; a situation that has been exploited by Isis and other Sunni insurgent groups.

The International Organisation for Migration (IOM) estimated that 500,000 people fled their homes in and around Mosul last week, with many seeking refuge in the autonomous Kurdistan region.