The Iraqi parliament is scheduled to meet on July 13 in a fresh bid to start forming a new government to deal with a rising Sunni insurgency.
The parliament elected in April met for the first time on July 1 but failed to agree on nominations for the top three government posts.
The UN special envoy to Iraq, Nickolay Mladenov, warned of chaos if divided lawmakers did not make progress on July 13 towards naming a new government.
The White House said U.S. Vice President Joe Biden talked on July 12 with Masoud Barzani, president of the Iraqi Kurdistan Region, and discussed the need to form a new government and peacefully resolve territorial disputes.
In a hopeful sign, the main Sunni political coalition late on July 12 chose lawmaker Salim al-Jabouri, a moderate Islamist, as its nominee for parliament speaker.
Prime Minister Nuri al-Maliki, who has ruled the country since 2006, is under pressure to step aside.
His government's inability to prevent the attack, let alone roll back the militant advance, has sparked doubt in Iraq and abroad over his ability to hold Iraq together and lift it out of the crisis.
Al-Maliki's opponents, and even many of his former allies, accuse him of trying to monopolize power and alienating the Sunni community.
Al-Maliki has so far refused to withdraw his candidacy, and points to his State of Law bloc's capturing the most seats in April elections to claim he has a mandate.
On July 12, Iraqi troops supported by Shiite militiamen battled Sunni militants who had seized at least partial control of a military base outside the town of Muqdadiyah, about 90 kilometers north of Baghdad.
To the west of Baghdad, the government airlifted some 4,000 volunteers to Ramadi to boost their forces trying to defend the city from militant attack, said General Rasheed Flayeh, the commander of operations in Anbar province.
Based on reporting by Reuters, AP, and AFP