Iraq has said the US must provide a "very clear timeline" to withdraw its troops from the country.

Iraqi Foreign Minister Hoshiyar Zebari said it is required as part of an agreement to allow US troops to stay beyond this year.

US President George W Bush has long resisted setting a firm schedule for pulling troops out of Iraq.

Last month, however, the White House began speaking of a general "time horizon" and "aspirational goals" to withdraw.

Mr Zebari said the agreement, including the timeline, is "very close" and would probably be presented to the Iraqi parliament in early September.

Asked whether Iraq would accept an agreement without firm dates for troop withdrawal, Mr Zebari said: "definitely there has to be a very clear timeline."

But he said the exact timing is still under discussion.

"You may hear many dates but really I caution you to not pick any of these dates until you get the final document," Mr Zebari said.

The agreement will replace a UN Security Council resolution authorising the US presence, which expires at the end of this year.

Mr Zebari said he was confident the final document would be acceptable to both sides, and many compromises had been reached.

A sticking point in the negotiations has been Washington's wish that its troops be immune from Iraqi law.

In July, Iraq's deputy speaker of parliament said lawmakers would likely veto any a deal if this condition were granted.

Other hurdles include the power of the US military to detain Iraqi citizens, and their authority to conduct military operations, Mr Zebari said.

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