Militants pushed a week-long offensive that has overrun swathes of Iraq to within 60 kilometres (37 miles) of Baghdad on Tuesday, as the United Nations (UN) warned the country's very existence was under threat.
Washington meanwhile deployed extra troops to protect its embassy in Baghdad and was mulling air strikes against militants whose swift assault has seen them capture Mosul, a city of two million people, and subsequently a vast amount of territory north of Baghdad.
Iraqi officials have insisted they are making progress in repelling the fighters, who are led by the powerful Islamic State of Iraq and the Levant (ISIL) jihadist group, but have continued to lose ground. The crisis has displaced hundreds of thousands of people and sparked fears that the violence could impact the country's vast oil production, along with concerns that security forces won't be able to halt the insurgents' march on the capital.
Officials said Tuesday that the fighters briefly held areas of Baquba, a short drive from Baghdad, and took control of most of Tal Afar, a strategic Shiite-majority town in north Iraq that lies along a crucial corridor to Syria. The overnight attack on Baquba, which was pushed back by security forces, marked the closest that fighting has come to the capital as part of a lightning offensive in which jihadists have said they intend to march on Baghdad and the southern Shiite holy city of Karbala.
Tal Afar gains
In Tal Afar, militants were controlling most of the town but pockets of resistance remained, and soldiers, policemen and armed residents held on to parts of its airport, according to Nineveh provincial council deputy chief Nureddin Qabalan.
The swift advance of the militants has sparked international alarm, with UN envoy to Baghdad Nickolay Mladenov warning that Iraq's sovereignty is at stake. "Right now, it's life-threatening for Iraq but it poses a serious danger to the region," Mladenov told AFP. "Iraq faces the biggest threat to its sovereignty and territorial integrity in years," he added.
Another sombre warning came from the prime minister of Iraq's autonomous Kurdistan region, who told the BBC it would be "almost impossible" for the country to return to how it was before the offensive was launched on June 9.
Nechirvan Barzani said it would be difficult to find a resolution with Iraqi Prime Minister Nuri al-Maliki in power and recommended an autonomous region for Sunnis as a potential solution.
"Now we have to sit down and find a solution, find how to live together... but if we expect, if we think that Iraq will go back like before Mosul, I don't think so, it's almost impossible."
Alarmed by the militant advance against an Iraqi army that has largely wilted in the face of the onslaught, foreign governments have begun evacuating their nationals and pulling out diplomatic staff.
US President Barack Obama announced that about 275 military personnel were being deployed to Iraq to help protect the embassy in Baghdad and assist US nationals there, noting that they were "equipped for combat".
Washington has already deployed an aircraft carrier to the Gulf, but Obama has ruled out a return to combat in Iraq for US soldiers, who left the country at the end of 2011 after a bloody and costly intervention launched in 2003.
As the US weighed its next move, Secretary of State John Kerry said on Monday that drone strikes could be used, and while Washington has ruled out cooperating militarily with Tehran, the two nations – which have been bitter foes for more than 30 years – held "brief discussions" on the crisis in Vienna.
Doubts are growing that the Iraqi security forces can hold back the militant tide, despite military commanders trumpeting a counter-offensive. Soldiers and police retreated en masse as the insurgents, which included ISIL but also a litany of other groups including supporters of executed dictator Saddam Hussein, swept into Iraq's second city of Mosul a week ago, leaving vehicles and even uniforms in their wake.
Their retreat, despite their vast numerical advantage, is the result of what experts say are myriad problems, ranging from lacklustre training and low morale, to corruption and an atmosphere of simmering sectarianism. "This army is not a mature force," said Anthony Cordesman of the Centre for Strategic and International Studies.
Zaid al-Ali, author of the recent book, The Struggle for Iraq's Future, added that the army "does not have the capacity nor... the will to engage in close combat with ISIL or the other armed groups."
The jihadists are said to have killed scores of Iraqi soldiers as they pushed their advance, including in a "horrifying" massacre in Salaheddin province that has drawn international condemnation.
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