Iraqi families fleeing violence in the northern city of Tal Afar, arrive at the Kurdish checkpoint in Aski kalak, 40 km West of Arbil, in the autonomous Kurdistan region, on Tuesday. Saudi Arabia pledged $500 million in humanitarian aid for Iraq to be disbursed through the United Nations to those in need regardless of sect or ethnicity, state media reported. photo: afp

The US and UN have sharply criticised Iraqi leaders, warning time is running out after chaos in parliament despite calls for unity in the face of a Sunni militant offensive.

Iraq Prime Minister Nuri al-Maliki offered an amnesty to some backers of a sweeping militant offensive, in an apparent attempt to undercut support for the insurgents.
The offer comes after a farcical opening to the new parliament, despite world leaders calling on Iraq's fractious politicians to unite urgently to help combat insurgents, as the military struggles to seize the initiative.
Maliki's surprise move, made in his weekly televised address, appeared to be a bid to split the broad alliance of jihadists, loyalists of executed dictator Saddam Hussein and anti-government tribes that has captured large chunks of five provinces, displacing hundreds of thousands of people.
The vast majority of Iraq's Sunni Arab minority do not actively support the Islamic State (IS) jihadist group spearheading the offensive, but analysts say anger over perceived mistreatment by the authorities means they are less likely to cooperate with the security forces.
A major Sunni Arab militant offensive, spearheaded by jihadists from the Islamic State group, has overrun large areas of five provinces since June 9.
Iraqi security forces folded under the weight of the initial onslaught, in some cases shedding uniforms and abandoning vehicles to flee. They are now performing better, but are still struggling to regain lost territory.
Tuesday's first session of parliament since April elections ended in chaos, with so many Sunni and Kurdish deputies staying away after a break meant to soothe soaring tempers that the quorum was lost and a speaker could not be elected.
Washington quickly warned that "time is not on Iraq's side", with State Department spokeswoman Marie Harf calling for "extreme urgency".
UN special envoy Nickolay Mladenov said Iraqi politicians "need to realise that it is no longer business as usual".
Under a de facto agreement, the premier is a Shia Arab, the speaker Sunni Arab and the president a Kurd.
Meanwhile, Maliki yesterday rejected an assertion by the country's autonomous Kurdish region that its control of disputed territory is here to stay.
He was responding to remarks by regional president Massud Barzani last week that there was no going back on Kurdish rule in the oil-rich northern city of Kirkuk and other towns now defended by Kurdish fighters against Sunni militants.