Iraq could be facing a break-up as a result of an insurgency by Islamist militants, the country's former prime minister has warned.

Ayad Allawi, who was prime minister of Iraq's transitional government between 2004-2005, told BBC Newsnight that the crisis was the "worst" he had seen in the country for 30 years.

He also warned that military intervention by the United States could act as "fuel to the fire" in the conflict.