BAGHDAD — Opposition lawmakers shouted and pounded their desks in protest Thursday in a second day of emotional debate in parliament over a proposed agreement with the U.S. that would allow American forces to stay in Iraq for three more years.

At least three parliamentary factions, including lawmakers loyal to Shiite leader Muqtada al-Sadr, are fighting the agreement. But their opposition is not expected to prevent it from passing.

"The agreement ushers in a new occupation of Iraq, the duration of which we cannot tell," said Ajeel Abdul-Hussein, the senior Sadrist lawmaker.

If approved, the security pact would for the first time establish a clear timetable for the withdrawal of American forces from Iraq, and it would give Iraqi authorities far more oversight over the U.S. military presence than they currently have. It took nine months to negotiate the deal.

Prime Minister Nouri al-Maliki went on national television Tuesday to tell Iraqis the agreement is a step toward full sovereignty and to reassure neighboring Syria and Iran that he will not allow Iraq to be a base for attacks against them.

Sadrist lawmakers disrupted a reading of the proposed agreement for the second straight day. On Wednesday, they scuffled with security guards after one of them aggressively approached the bench while a lawmaker from the ruling Shiite coalition was reading the text.

On Thursday, they attempted to drown out the lawmaker reading it. Shouting matches broke out and Speaker Mahmoud al-Mashhadani was barely able to control the chaos that lasted about 20 minutes.

Parliament managed to complete the second reading, the last step prior to opening debate on the pact ahead of a vote scheduled for Monday. However, the disruptions on Wednesday could delay the vote by a day or two.

Ali al-Adeeb, a Shiite lawmaker close to al-Maliki, said it was necessary for American forces to remain in Iraq because of the insurgency even if the government, like opposition lawmakers, saw the U.S. presence as "unwanted."

Al-Maliki warned the alternative to the security pact — a renewal or an extension of the U.N. mandate providing legal cover for U.S. forces in Iraq — is worse.

"The danger of an extension is the removal of Iraq's sovereignty and facing the same problem again, which will drive us back to searching for another agreement" with the Americans, al-Maliki told a news conference.

He assured Iraqis the timeline for the withdrawal of U.S. forces under the agreement — out of cities by June 30, 2009, and the entire country by the end of 2011 — is not negotiable and could even be moved up.

The Cabinet approved the agreement last weekend, meaning the pact stands a good chance of passage in 275-seat parliament where the government's parties dominate.