In Baghdad, which is threatened by the rebel advance, top Shi'ite, Sunni and Kurdish MPs scrambled to agree cabinet nominations before parliament meets on Tuesday.
They are bidding to stop the advance by al Qaeda offshoot the Islamic State in Iraq and the Levant (Isis) jeopardising Iraq's future, with Prime Minister Nuri al-Maliki's political future after eight years in power the most contentious issue.
Across the frontier in Syria, it was reported that Isis fighters crucified eight men in the northern Aleppo province.
The Britain-based Syrian Observatory for Human Rights said Isis accused the men of being rival fighters controlled by the West. The men were said to have been crucified in the town square of Deir Hafer and would be left there for three days
Troops backed by helicopter gunships began an assault on Tikrit on Saturday, to take it back from insurgents who are within driving range of Baghdad.
The assault came from the direction of Samarra to the south, where the military has drawn a "line in the sand" against the insurgents' advance toward Baghdad.
Yesterday the army sent tanks and helicopters to battle Isis militants near the University of Tikrit in the city's north.
The offensive was the first major bid by the army to retake territory after the United States sent 300 advisers and drone aircraft to help the government take on Isis.
Iraqi army spokesman Qassim Atta said security forces had killed 142 "terrorists" over the last 24 hours across Iraq, including 70 in Tikrit, and the armed forces were in control of the university.
"Our security forces have taken complete control of the University of Tikrit and they have raised the Iraqi flag on top of the building," Mr Atta said.
He added that militants were struggling because "their morale has started to collapse," but insurgents, backed by some local Sunnis, kept control of Tikrit yesterday.
At least four people were killed, including two women, when helicopters attacked a gathering for a wedding ceremony near Tikrit on Saturday, witnesses said.
Yesterday intermittent clashes broke out between militants and government forces in the outskirts of the town of Jurf al-Sakhar, 53 miles south of Baghdad.
Earlier yesterday, Deputy Prime Minister for Energy Hussain al-Shahristani, one of Iraq's most senior politicians, accused the US of not doing enough to bolster the country's military.
Just hours after Russia delivered five Sukhoi jets to the Iraqi government, he suggested that the US had been more helpful to Israel than to Iraq. US officials have in the past said they have done everything possible to ensure Iraq has modern weaponry.
Iran has also backed Iraq's government against the onslaught. An Iranian general said yesterday his country was ready to help Iraq fight the revolt using the same methods it deployed against rebels in Syria.
"With Syria … we would not allow terrorists in the hire of foreign intelligence services to rule and dictate to Syrian people. We will certainly have the same approach with Iraq," Brigadier General Massoud Jazayeri said.