Khalilzad was speaking two days after Shi'ite and Kurdish negotiators pronounced the draft "final" despite objections by Sunni negotiators.
Although the law does not allow the draft to be amended, Khalilzad said there can be what he called "edits" to the text. He said he believes a "final, final" draft has not yet emerged.
Khalilzad spoke alongside prominent Sunni leader Adnan al-Dulaimi. Al-Dulaimi urged Sunnis to reject the constitution as it is now written in a scheduled 15 October referendum.
Elsewhere in Iraq, the U.S. military said today in a statement that it bombed what it described as "terrorist safe houses" near the Iraqi border with Syria. The U.S. military said the raids killed "several militants."
But Iraqi sources claimed the air strikes killed at least 45 civilians. Local Iraqi hospital and security sources disputed the U.S. claim that three bombing raids near the town of Qaim successfully hit terrorist hideouts and killed an Al-Qaeda associate named Abu Islam, among others.
Neither claim could be verified.
Speaking at a naval base in Colorado to mark the 60th anniversary of the end of World War II today, U.S. President George W. Bush said the same resolve that won World War II is needed to defeat terrorism and turn the tide in Iraq.
It was Bush's third speech about Iraq or the war on terrorism in less than two weeks. Polls show a majority of Americans now believe the invasion of Iraq was a mistake.
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