At what one senior Western diplomat said was a "moment of truth" for Iraq's elected leaders, the Shia premier refused to accept the resignation of six Sunni members of his cabinet and promised to discuss their concerns.

Prime Minister Nuri al-Maliki on Sunday met President Jalal Talabani, who is a Kurd, and Vice President Adel Abdel Mehdi, a fellow Shia.

Tellingly, Vice President Tareq al-Hashemi, the senior Sunni Arab in the government and a critic of Maliki's alleged sectarian bias, was not present, but his colleagues vowed to hold inclusive talks in the coming days.

"The prime minister's position is that he has refused to accept the resignations. This is a good thing and the door is open to discuss this topic," Abdel Mehdi announced after the meeting.

On Wednesday, Iraq's main Sunni political bloc the National Concord Front said it was withdrawing its five ministers and deputy prime minister from the coalition, dealing a blow to the government's claims to represent all Iraqis.

Since the US-led invasion of March 2003, Iraq has plunged into an abyss of overlapping civil conflicts that have divided its rival religious and ethnic communities, and left tens of thousands of civilians dead.

Last year's formation of an elected government of national unity held out the promise of reconciliation, but Maliki's rule has been undermined by bitter sectarian rivalries both within and outside his fragile coalition.