Leaders of the commission investigating the 2001 terrorist attacks on the United States are downplaying differences with the White House over a possible link to Iraq. But at the same time, they make clear they want more information from top figures in the Bush administration.

The two men at the top of the commission are trying to prevent a partisan split between Republicans and Democrats on the panel. As a result, they are trying to ease differences over a potentially explosive issue: ousted Iraqi leader Saddam Hussein's ties to the al-Qaida terrorist network.

In a staff report issued a few days ago, the commission said there was no evidence that Saddam Hussein collaborated with al-Qaida in attacks on the United States. Commission staffers said they found proof of contacts but no working relationship.

But the White House - which used Iraq's ties to terror as a rationale for war - continues to insist there was a direct connection to al-Qaida. On Thursday, after the commission released the interim staff report, Vice-President Dick Cheney indicated that he had information that was not in the hands of the panel. He spoke in an interview with CNBC - a cable television outlet in the United States.

Reporter: "Do you know things that the commission does not know?"
Cheney: "Probably."
Reporter: "And do you think the commission needs to know them?"
Cheney: "I don't know what they know. I do know they did not talk with any original sources on this subject that say that [are quoted] in their report."

When asked about those comments, Commission Chairman Thomas Kean urged the vice-president to turn over any additional information he might have. Appearing on ABC television's This Week, Mr. Kean stressed the staff report was an interim document and the final full commission report remains a work in progress. "Obviously, if there is any information still that has to deal with the subject of the report, we need it and we need it pretty fast. We'll ask for it and see. If the administration has information we don't have, then hopefully we will have it very soon," he said.

Thomas Kean is the top Republican on the independent panel which was established by Congress with the approval of the White House. Lee Hamilton is the senior Democrat. He joined the call for any additional information that might be in the possession of the vice-president. And he told ABC that any apparent differences with the administration on the issue of Iraqi links to al-Qaida may be a matter of semantics. "All of us understand that when you begin to use words like 'relationships' and 'ties' and 'connections' and 'contacts,' everybody has a little different view of what those words mean," he said.

Both Chairman Kean and Vice Chairman Hamilton emphasized that the commission's task is to investigate the September 11 attacks, and not the run-up to the war in Iraq. They noted that while the Bush administration has spoken about Saddam Hussein's ties to terror, it has never said that Iraq teamed with al-Qaida to actually carry out the worst terrorist attack ever on American soil.

On NBC's Meet the Press, commission member John Lehman made clear he hopes the controversy over this one issue dies down, noting the panel needs to avoid potential partisan disputes as it prepares its final recommendations. "I think that you are going to see unanimous recommendations on the intelligence community from our commission. And they are going to be based on shocking findings of gross malfunctions in the intelligence community," he said.

The commission's report is due on July 26. The White House will review the document to make sure no sensitive national security information is revealed before it is released to the public.