Tearful relatives of Sept. 11 victims urged White House officials Wednesday not to block Congress' plans to create an independent commission to investigate the attacks.

About 10 relatives met on Capitol Hill with lawmakers and two White House officials, Nicholas Calio and Jay Lefkowitz, in an unsuccessful attempt to break a deadlock over the commission.

Lawmakers are looking to create a commission that would go beyond the limited inquiry into intelligence failures that the House and Senate intelligence committees are winding down. The committees hold their final public hearing Thursday, with CIA Director George Tenet and FBI Director Robert Mueller expected to respond to criticism of their agencies.

After initially opposing the independent commission, the White House now says it supports it. But it has differences with the families and congressional leaders about the commission's leadership and its subpoena power.

Rep. Porter Goss, R-Fla., chairman of the House Intelligence Committee, has indicated he won't let the commission be considered in Congress until an agreement is reached with the White House.

"Our frustration level has never been higher," said Beverly Eckert of Voices of Sept. 11.

The relatives and their congressional supporters said they are waiting to hear back from the White House.

"We left the meeting with the ball not just in the White House's court, but firmly with them at the free throw line with a couple of seconds left in the game," said Rep. Tim Roemer, D-Ind.

The main sticking points continue to be provisions governing the commission's subpoena power and leadership, which the White House fears could lead to partisan squabbling and finger-pointing. Bush objects to a provision that would allow five members of the 10-person commission, split evenly between Democrats and Republicans, to issue a subpoena. The administration also wants to be able to appoint more than one member.

"Unfortunately there still are some members (of Congress) who do not share the view that this commission should be truly bipartisan," White House spokesman Scott McClellan said. "We hope these members will reconsider."

Bush aides were meeting Wednesday evening to press their case with the relatives.

Under the plan worked out by Democratic and Republican lawmakers, the commission would last two years and would explore a wide range of issues related to the Sept. 11 attacks, including intelligence, aviation security and immigration. The one-year congressional investigation examined only issues related to intelligence.

At Thursday's inquiry hearing, Tenet is expected to describe CIA efforts to stop terrorism before Sept. 11. While acknowledging some shortcomings, Tenet will say generally that "people in the intelligence community perform their jobs extraordinarily well," said a U.S. intelligence official speaking on condition of anonymity.

"He will take the opportunity -- not in a defensive way, just for a matter of record -- to help dispel some misinterpretations that may have arisen," the official said.

The staff of the congressional inquiry has found no single piece of information in the hands of intelligence agencies which, by itself, pointed to the Sept. 11 attacks. But they have found various clues they believe might have led to the plot if they had been pieced together.

The top Republican on the Senate Intelligence Committee, Sen. Richard Shelby of Alabama, noted that in an appearance before his panel in February, Tenet said he was proud of the CIA's counterterrorism record.

"He was in denial last time we had a public hearing," Shelby said. "He was denying that there were intelligence failures. It's interesting to see if he's changed his mind."

Intelligence officials suggested Shelby must have misunderstood Tenet's testimony in February.