A suicide bomber has struck in Baghdad, killing at least nine people and injuring at least 20 more, according to local officials in crisis-hit Iraq.

An interior ministry official claimed the attack was a roadside bomb, while a police colonel said that was then followed by a suicide bombing.

Police said an attacker wearing an explosive vest detonated his device near Tahrir Square in central Baghdad. An eyewitness told AP the explosion happened outside a shop selling military fatigues.

The bomb is the latest escalation in the Iraq crisis. An extreme Sunni militant group, the Islamic State of Iraq and the Levant (Isis), has already taken control of the country's second city of Mosul. In recent days Isis has led violent sectarian attacks against the Shiite-led Iraqi government. They have captured several cities and are heading north to Baghdad. Iraqi military commanders say government forces have retaken two towns north of the capital.

Today former UK Prime Minister Tony Blair, who backed a US-led invasion of Iraq in 2003 and committed thousands of British troops to support US forces – said the invasion was not to blame for the current uprising in Iraq.

He insisted that the latest conflict in Iraq was caused by the ineffective and sectarian administration of Prime Minister Nouri al-Maliki and the civil war in neighbouring Syria.