Washington ? Amid calls for a shake-up of the nation’s intelligence operations, the heads of the FBI and the CIA on Wednesday defended their agencies before the commission investigating the Sept. 11, 2001, attacks and said reforms were under way to correct past mistakes.

At the same time, the commission issued scathing reports on failures at the two agencies, concluding that despite a “cacophony of activity” within the intelligence community, there still isn’t a national strategy for sharing counterterrorism information.

In an unusually frank admission, CIA Director George Tenet told the panel: “We made mistakes. We all understood (Osama) bin Laden’s attempt to strike the homeland, but we never translated this knowledge into an effective defense of the country.”

Under questioning from Democratic commissioner Timothy Roemer, Tenet revealed that in August 2001 — when the threats were so serious that they were “blinking red,” he said — he didn’t meet or talk with President Bush. CIA staff members briefed Bush, who spent much of that month at his ranch in Crawford, Texas.

Commissioners warned Tenet and FBI Director Robert Mueller that they’re weighing an overhaul of the intelligence community.

But Mueller said in his testimony Wednesday afternoon that “it would be a grave mistake” to create a separate domestic intelligence agency. He warned that such an agency, modeled after Britain’s MI-5, might not protect civil liberties in the same way the FBI is legally bound to.

“Splitting up intelligence and law enforcement will leave both agencies with one hand tied behind their backs,” Mueller said.

But commission Chairman Thomas Kean said he was deeply troubled by reports of the FBI failing “over and over again.”

The commission’s staff report said the FBI still suffered from a shortage of translators, agents to do surveillance on terrorist suspects and reliable sources within the Islamic community.

CIA director George Tenet gestures testifies before the commission investigating the Sept. 11 attacks on Capitol Hill. Tenet on Wednesday acknowledged that mistakes were made in estimating al-Qaida's intent on attacking the United States.

In addition, problems persist with the bureau’s analysts, a centerpiece of the FBI’s drive to become more intelligence-driven.

The head of the FBI’s Washington field office told commission investigators as recently as last August that he couldn’t e-mail staff at the Department of Justice from his desk. And the field office, the second largest in the country, had just one Internet terminal per floor.

“Can you fix it?” Kean asked Mueller. “Because the FBI is absolutely essential to this war we’re talking about.”

“I think we can and are fixing what is wrong with the FBI,” Mueller responded. “Change cannot be done overnight.”

The bureau is in the process of hiring 900 intelligence analysts, updating its archaic computer system and working to bring on more translators in Arabic, Farsi and other Middle Eastern languages.

“The bureau is moving steadily in the right direction,” Mueller said.

Tenet said it would take five more years to fully rebuild the agency’s clandestine service to infiltrate terror cells and recruit informants overseas. The eavesdropping National Security Agency and other intelligence agencies are also years away from being on proper footing, Tenet said.