Updated

Vice President Dick Cheney said Thursday that congressional Democrats need to be "very cautious" about their criticism of the Bush administration's decision not to disclose intelligence before Sept. 11 that terrorists wanted to hijack U.S. airplanes.

In a speech at the New York state Conservative Party's annual dinner, Cheney warned Democrats "to not seek political advantage by making incendiary suggestions ... that the White House had advance information that would have prevented the tragic attacks of 9/11."

"Such commentary is thoroughly irresponsible and totally unworthy of national leaders in a time of war," he said.

The White House has acknowledged that in the weeks before the Sept. 11 attacks, President Bush was told by U.S. intelligence that Usama bin Laden's Al Qaeda terrorist network might hijack American airplanes. That prompted the administration to issue a private warning to federal agencies.

The public was not informed of the threats, which administration officials called vague and uncorroborated. But congressional Democrats have demanded to be told what the president knew about terrorist threats before the attacks.

At the behest of the president, Cheney said he is working with House and Senate leadership to investigate any intelligence failures. He also said the White House would cooperate fully with the probe, but he urged that it be handled professionally.

"The investigation undertaken must protect sensitive sources and information, must be devoid of leaks and it must avoid sensational and outrageous commentary," he said.

Cheney said that Democratic attacks could backfire.

"The people and agencies responsible to help us learn to defeat such an attack are the very ones most likely to be distracted from their critical duties if Congress fails to carry their obligation in a responsible fashion," he said.