Top US military and civilian leaders "have stated for quite some time our withdrawal from Iraq is going to be, we called, condition-based," said Navy Lieutenant Commander Joe Carpenter, a Pentagon spokesman.

The comments follow remarks from the British defense ministry that Washington and London are considering withdrawing more than 100,000 coalition troops from Iraq in 2006 as one of many options.

According to Carpenter, withdrawal conditions include successful political advances in Iraq such as the adoption of a Constitution and national elections, currently scheduled for early 2006.

It would also depend whether the security situation in Iraq has improved and that "the Iraqi security forces are in sufficient quantity and quality" to maintain order, Carpenter said.

"Our plan, our strategy is not driven by a date, it is driven by conditions in place," he said.

The US military "has any number of plans based on a variety of criteria," he said. "So that for many different scenarios there are plans in place where you can begin to develop a plan and take action."

Carpenter, however, said that he was "not aware of any specific plan that has a specific date for forces level in Iraq."

According to a document by British Defense Secretary John Reid, which was leaked to Britain's Mail on Sunday, Washington hoped to hand over control of security to Iraqi forces in 14 out of 18 provinces in the country by early next year, allowing it to slash US-led troop levels to 66,000 from 176,000.

Britain, for its part, had a plan to cut its 8,500-strong contingent to

The document -- entitled "Options for future UK force posture in Iraq" and marked "Secret -- UK eyes only" said London would need to reach decisions later this year on troop levels.

A British military spokesman confirmed the document's authenticity to AFP.