Iraq’s deadlocked parliament on Sunday failed to overcome the deep divisions hampering the formation of a new government, making no progress on choosing leaders who could help hold the nation together and confront the Sunni militant blitz that has overrun much of the country.

The legislature is under pressure to quickly choose a new speaker of parliament, president and prime minister — the first steps toward a new government. The international community has pressed lawmakers to put their differences aside, while the United Nations has warned of chaos if the political impasse drags on for too long.

But just 30 minutes into Sunday’s session, acting speaker Mahdi Hafidh announced that he was suspending the proceedings until Tuesday “due to the absence of any agreement on the names of the nominees for the three posts.”

Hopes had been raised that lawmakers might at least vote on a speaker after Sunni blocs announced Saturday that they had agreed on a candidate, Salim al-Jubouri. But even that proved difficult, and lawmakers dispersed amid mutual recriminations.

ASunni legislator, Saleh al-Mutlak, said Prime Minister Nouri al-Maliki agreed to support Jubouri’s candidacy on the condition that Sunnis back Maliki for a third consecutive term. “This will not happen as we do not accept that,” Mutlak said.

Under an informal arrangement after the 2003 U.S.-led invasion, the speaker’s position goes to a Sunni, the presidency to a Kurd and the prime minister’s post to a Shiite. The greatest disagreement is over prime minister, the most powerful position.

Maliki has been prime minister since 2006 but is under pressure to step aside. His opponents and many former allies accuse him of trying to monopolize power and alienating Sunnis. He has refused to withdraw.

The urgency for lawmakers to forge an agreement stems from the threat the nation faces from Sunni militants who swept across much of northern and western Iraq over the past month, raising the prospect of an Iraq cut in three along ethnic and sectarian lines.

On Sunday, the insurgents barreled unopposed into the town of Duluiyah, about 45 miles north of Baghdad, seizing the mayor’s office, police station, local council and courthouse, a police officer said. They also blew up a bridge that links the town with the predominantly Shiite city of Balad.

The military launched a counterattack that drove the militants from some parts of Duluiyah, but clashes were still raging, the officer said, adding that six members of the security forces and six pro-government Sunni militiamen were killed in the fighting.

The insurgents are led by the Islamic State extremist group, which has declared the establishment of an Islamic state in the territory it has seized straddling the Iraq-Syria border.