Will Iraq turmoil lead to break up?

Fresh clashes have been reported between jihadist-led Sunni rebels and government forces around the Iraqi city of Tikrit.

The violence comes a day after the Islamic State in Iraq and the Levant (Isis) announced the creation of a "caliphate".

The turbulent situation means the government in Baghdad is under ever increasing pressure to try and prevent the break up of the country, as Jeremy Bowen reports.