The government is confident of the pact's approval by a simple majority despite angry opposition from some MPs.

"The debate has finished and the vote will take place on Wednesday," speaker Mahmud Mashhadani said after a seven-hour session on Saturday during which about 40 MPs expressed their views.

If the three main blocs, Sunnis, Shiites and Kurds, can agree a joint position, the vote could even take place before Wednesday, he added.

On Saturday, in the third reading since last Monday, Kurds spoke out about differences they have with the government while Sunni and Shiite MPs appeared divided amongst themselves on the proposed Status of Forces Agreement.

"Errors were committed during the negotiations which were conducted without transparency and with neither parliament nor the people being kept informed," said a leader of the 53-member Kurdish Alliance parliamentary faction.

His comments could put at risk the group's previous support for the agreement.

"As a Kurd I think settling the problems of Kurdistan is more important than the deal and we must find a consensus on internal matters as it is the unity of Iraqi people which will force the United States to enforce the pact," he added.

The two main Kurdish parties are upset by the formation of tribal Support Councils at the initiative of Prime Minister Nuri al-Maliki, saying he wants to create his own militias to tighten Baghdad's grip on ethnically-mixed regions.

Iraq's presidential council demanded on Friday that Maliki suspend the tribal councils so their legality can be reviewed.

The Shiites' biggest parliamentary group, the 85-MP United Iraqi Alliance, expressed its support for the pact with the United States, through Hadi al-Ameiri.

"It is not the ideal choice but it is the best choice because at least it sets a timetable for the departure of American troops," he said.

However, Hassan Shamari of Fadhila, which has 15 Shiite MPs, said: "The immunity granted to American soldiers violates sovereignty."

Supporters of firebrand Shiite anti-American cleric Moqtada al-Sadr, who include 30 MPs, have opposed the deal from the start. Thousands gathered in Baghdad on Friday to protest against the accord.

"The deal was written by American hands and the government has been obliged to sign it. It damages Iraq's soveregnty," Nassir al-Isawi said.

Sunnis, with 56 MPs, are hostile to the plan except for Mashhadani and the 10 MPs in his group. "We support the agreement because it is the least bad alternative," he said.

To be approved, the SOFA needs 138 votes from the 275 MPs.

Parliament has no right to modify the articles of the agreement, which provides for US troops to leave Iraqi cities and other major locations by mid-2009 and to exit the country by the end of 2011.

Iraq's cabinet approved the agreement on November 16. It also has to be ratified by Iraq presidential council before being signed by both countries.