Iraq today said it had "regained the initiative" against militants who seized vast swathes of territory, as former UN mediator Lakhdar Brahimi blamed the crisis on global neglect of Syria's civil war.
Washington responded to the sweeping unrest by deploying an aircraft carrier to the Gulf, but Iran has warned against foreign military intervention in its Shiite neighbour, voicing confidence that Baghdad is able to repel the onslaught.
The militants, spearheaded by the powerful Islamic State of Iraq and the Levant (ISIL) jihadist group, have overrun all of one province and chunks of three more since they launched their offensive late on Monday.
Security forces have generally performed poorly, with some abandoning their vehicles and positions and discarding their uniforms, though they seem to have begun to recover from the initial onslaught and have started to regain ground.
Iraqi commanders have said their forces were now starting to push the militants back, and that soldiers had recaptured two towns north of Baghdad, with a spokesman announcing that Iraqi security personnel had killed 279 "terrorists" in the past 24 hours.
Iraqi officials however often announce large militant tolls, with no way of independent verification, and downplay their own casualties.
Prime Minister Nuri al-Maliki's security spokesman, Lieutenant General Qassem Atta, also said during a televised news conference that Baghdad had "regained the initiative".
Baghdad's forces will be joined by a flood of volunteers, urged on by a call to arms from top Shiite cleric Grand Ayatollah Ali al-Sistani.
A recruitment centre for such volunteers at the town of Khales in central Iraq came under mortar attack today, leaving six people dead, including three Iraqi soldiers, police and a doctor said.
US President Barack Obama said he was "looking at all the options" to halt the offensive that has brought the militants within 80 kilometres of Baghdad's city limits, but ruled out any return of US troops to combat in Iraq.
Washington has, however, ordered an aircraft carrier into the Gulf in response to the crisis.