Iraqi leaders missed another deadline to sign the creation of an interim constitution after last-minute wrangling wrecked a carefully planned signing ceremony, as security in Baghdad was on heightened alert. As guests and members of a children's choir lost patience waiting for the council members to appear and left, an official from the US-led coalition told weary reporters to go home after an eight-hour wait. The delay arose after Shiite leaders expressed concern that a clause in the document could give the Kurdish community a veto power in the future when a referendum is to be held on Iraq's permanent constitution. The signing ceremony had already been pushed back from Wednesday out of respect for more than 170 people killed by bombings in Baghdad and Karbala a day earlier. It has not been officially rescheduled, though an advisor to interim Governing Council member Adnan Pachachi told AFP that they will meet again early Saturday. Senior coalition spokesman Dan Senor was adamant the delay would be resolved soon. "Democracy is messy whether it is in Baghdad, Washington or London," he told reporters. The coalition however had clearly expected the text to be stamped on time. The interim constitution, due to come into force on July 1, is aimed at seeing Iraq through a transitional period and into next year. It will make Iraq a federal state with two official languages where Islam will be a source of legislation, but not the basis for it. Meanwhile security was high in Baghdad as the leaders haggled. Extra checkpoints had been set up and security forces deployed in force around Saddam Hussein's former assembly complex where it is taking place. Hours before the ceremony was to get underway, a number of mortar rounds hit the northern part of Baghdad International Airport, now a US base. A military spokesman said there were no casualties. Other unexplained blasts were heard around the capital, the scene of some rocket attacks in the past 24 hours. Meanwhile in London, former UN chief weapons inspector Hans Blix criticized British Prime Minister Tony Blair in an interview published Saturday, saying that Blair lacked "critical thinking" in the run-up to the Iraq war. Speaking from his home in Stockholm, Blix told the London-based Guardian daily that he was not accusing Blair of bad faith in taking Britain to war. "What I am saying is there was a lack of critical thinking," Blix said. In the United States, investigators continued their probe into whether top Bush aides illegally leaked the name of a covert CIA agent who was the wife of a prominent critic Iraq war critic. The disclosure may be a crime. Investigators have requested records of telephone calls from the president's airplane, Air Force One, the White House said Friday. The investigators are hunting for who told columnist Robert Novak that Valerie Plame was an undercover CIA operative working on the weapons of mass destruction issue. The disclosure may be a crime. Plame's husband, former ambassador Joseph Wilson, publicly revealed last year that he had investigated charges that Iraq sought uranium from Africa and reported back to the Bush administration that they were false. Bush used the allegation subsequently in his 2003 State of the Union speech, and Wilson has contended that the administration leaked his wife's identity to punish him for his disclosure. Plame's name and her CIA ties were revealed in a July 14 2003 opinion column by Novak, who sourced it to two senior administration officials. **PHOTO CAPTION*** Ali Murtada, six, performs in front of Iraqi ministers and officials waiting for the start of the signing ceremony of Iraq 's temporary constitution at Baghdad's Convention Center. (AFP/Joseph Barrak)