The cross-sectarian Iraqiya alliance of former Premier Iyad Allawi said on Thursday it might boycott Monday's session, called to try to break a political deadlock that has stoked tensions in Iraq as US troops prepare to depart.

But incumbent Prime Minister Nuri Al-Maliki's Shiite allies and the Kurdish lawmakers who appear set to back him for a new term may be able to muster a quorum without Iraqiya.

They may even be helped in that by a group of Iraqiya lawmakers who disagree with its steadfast refusal to support Al-Maliki for a second term, and also by another bloc of mainly Sunni lawmakers who seem willing to ally themselves with him.

"We are not ready to delay the formation of the government any longer than this and we are with anyone who can get half of the parliament plus one," said one of the dissenting Iraqiya parliamentarians, Ahmed Al-Ureibi. Others shared his stance. Deciding which faction gets the post of speaker is the first piece of a jigsaw puzzle that could lead to the selection of a president and prime minister, though not necessarily right away.

The posts are expected to be divided along ethno-sectarian lines, a sign of the deep divisions that run through Iraq 7-1/2 years after the US-led invasion triggered ferocious sectarian warfare between once dominant Sunnis and majority Shiites.

Al-Maliki, a Shiite, and President Jalal Talabani, a Kurd, appear to have enough support to secure their reappointments.

They want the speaker post to go to a Sunni in Iraqiya, which won two more seats in the March 7 election than Al-Maliki's bloc after gaining strong support among minority Sunnis.

US officials fear excluding Iraqiya from the government could anger the Sunni voters who supported it and pour new fuel on a weakened but still lethal insurgency.

A siege of a Catholic church and a barrage of bombings around Baghdad have killed more than 100 people in the past few days, reminding Iraqis of the fragile state of their war-damaged nation and putting pressure on politicians to act.