BAGHDAD  - Followers of anti-American Shiite cleric Moqtada al-Sadr were making a bid on Monday to kill a controversial Iraq-US military pact passed by the Iraqi cabinet by trying to block it in parliament.

The Sadrist movement has vigorously opposed the wide-ranging agreement, which would replace a UN mandate that expires at the end of the year and allow US forces to remain in the country until the end of 2011.

Ahmed Masaudi, spokesman for Sadr's 30-member parliamentary bloc, said the movement would submit a bill that would require a two-thirds majority for parliamentary approval, replacing the current requirement of a simple majority.

"(The current law) is contrary to the constitution and to the instructions from the Guide, Sistani, to obtain a national consensus on this agreement," Masaudi said on Sunday, referring to Grand Ayatollah Ali Husseini al-Sistani.

The country's most powerful Shiite cleric has not taken a clear position on the agreement other than to say it should respect Iraq's "sovereignty," and has left the decision to approve the deal to elected leaders.

But Sadr and his followers have adamantly opposed concluding any agreement with the US "occupier" and have vowed to hold mass demonstrations to demand the immediate withdrawal of all foreign forces.

"The Sadr movement will use every legal avenue to work to stop this agreement," Masaudi said, adding that the group was determined to form an alliance inside parliament to kill the proposed pact.

The 275-member parliament started its first reading of the proposed military accord on Monday after the deputy speaker said on Sunday the session would began a week-long process of deliberation before a final vote on November 24.

"Members of the legal committee have begun examining the draft agreement between Iraq and the United States on the withdrawal of American forces," a parliamentary source told AFP on Monday.

The pact was expected to pass parliament after winning approval from the Iraqi cabinet on Sunday with the support of the major political blocs representing Iraq's Shiite majority and its Sunni and Kurdish communities.

If parliament approves the pact it would need to be ratified by Iraq's presidential council before Prime Minister Nuri al-Maliki could sign the agreement with US President George W. Bush.

In a symbolic ceremony broadcast on state television before Monday's parliamentary session began, Iraqi Foreign Minister Hoshyar Zebari and US Ambassador Ryan Crocker applied their signatures to the pact.

"This is a historic day for relations between the United States and Iraq," Zebari said. "After difficult negotiations the cabinet has approved the agreement and sent it to parliament which will have the last word."

Crocker thanked the negotiating teams on both sides.

"It was complicated and tough negotiations, and all the Iraqis can be very proud of this agreement," he said.

US president-elect Barack Obama told CBS television on Sunday that when he takes office on January 20, "I will call in the Joint Chiefs of Staff, my national security apparatus, and we will start executing a plan that draws down our troops" from Iraq.