Baghdad: Iraq's Presidency Council has approved a security pact with the United States that paves the way for a complete US troop pullout by the end of 2011, a spokesman for the council said on Thursday.

The pact, which brings in sight an end to the US military presence that has lasted since the 2003 invasion, passed through parliament last month after protracted negotiations. It is supposed to be put to a public referendum next year.

Iraq's three-member Presidency Council, which includes President Jalal Talabani and his two vice presidents, must unanimously approve all legislation passed by parliament or it goes back to the house.

"The Presidency Council has endorsed the security pact with the United States. That means this pact is put into force," Presidency Council chief of staff Naseer Al Ani told reporters.

The council also gave the green light to a longer-term agreement defining cultural, economic and security ties between the two countries.

A joint statement by US Ambassador to Iraq Ryan Crocker and General Ray Odierno, commander of US forces in Iraq, said both agreements would now officially take effect after an exchange of diplomatic notes.

"We look forward, under these agreements, to the continued reduction in US forces and the normalisation of bilateral relations as two sovereign and co-equal nations," it said.

Iraq's government has tried to quell criticism of the security pact, saying opponents should wait to judge how Washington honours commitments to pull back its troops.