"Clearly there was no lack of care or focus in the face of one of the greatest dangers our country has ever faced," Tenet told the federal commission on the Sept. 11 attacks.
But in a preliminary report, the commission said CIA efforts to stop Osama bin Laden were hindered by confusion over whether intelligence officers were allowed to kill the al Qaeda leader.
The report also said that in August 2001, President Bush was briefed on terrorism but he was given no "specific, credible information about any threatened attacks in the United States."
Tenet appeared before the panel Wednesday, the second day of hearings with Bush and Clinton administration officials as the commission examines diplomatic, military and intelligence efforts to stop al Qaeda before the Sept. 11 attacks against New York and Washington.
The commission's findings are to be released this summer and are likely to provide fodder for both Republicans and Democrats in their fall election campaigns.
The preliminary report said that before the Sept. 11 attacks, "no agency did more to attack al Qaeda, working day and night than did the CIA." But the agency also ran into major problems.
President Clinton had issued several orders for "the CIA to use its proxies to capture or assault bin Laden and his lieutenants in operations in which they might be killed. The instructions, except in one defined contingency, were to capture bin Laden if possible."
While Clinton administration officials believed those orders authorized the CIA to kill bin Laden, many CIA officials — including Tenet — believed they were authorized only to capture bin Laden. "They believed the only acceptable context for killing bin Laden was a credible capture operation," the report said.
But Mr. Clinton's former national security adviser, Samuel Berger said the CIA never complained about the restrictions to the White House, the report said.
The CIA also had depended too much on Afghan indigenous groups to attack bin Laden, the report said. Local forces reportedly considered attacking bin Laden convoys about six times before Sept. 11. Each time the operation was aborted because bin Laden took a different route, security was too tight, or women and children were believed to be in the convoy.
Due to testify later Wednesday is Richard Clarke, the former counterterrorism chief for both Mr. Clinton and Mr. Bush. He claims that the Bush administration, fixated with invading Iraq,. The White House denied those charges.
The commission's report said the CIA's deputy director of operations, Jim Pavitt, told Mr. Bush shortly after he was elected that bin Laden was one of the gravest threats to the country.
"President-elect Bush asked whether killing bin Laden would end the problem. Pavitt said he and (Tenet) answered that killing bin Laden would have an impact but not stop the threat," the report said.
The CIA later told the White House that "the only long-term way to deal with the threat was to end al Qaeda's ability to use Afghanistan as a sanctuary for its operations."
After intelligence agencies began seeing strong indications in June and July 2001 that a terrorist attack was likely, some CIA officials were frustrated when some policy-makers questioned the intelligence. But Tenet, who was briefing Mr. Bush daily, "told us that his sense was that officials at the White House had grasped the sense of urgency he was communicating to them," the report said.
In August 2001, the CIA gave Mr. Bush a highly secretive assessment on whether terrorists might attack the United States. It included no "specific, credible information about any threatened attacks in the United States," according to a second report released by the commission Wednesday.
The White House was not informed about investigations that revealed that two al Qaeda operatives — both future hijackers — were in the United States.
In another preliminary report issued Tuesday, the commission said U.S. officials planned missile attacks on bin Laden after receiving intelligence on his whereabouts, but didn't proceed with the strikes because the intelligence came from a single, uncorroborated source and there was a risk of innocents being killed.
"George (Tenet) would call and say, 'We just don't have it,'" the report quotes Berger as saying.
Tuesday's report also said that both the Clinton and Bush administrations engaged in lengthy, ultimately fruitless diplomatic efforts instead of military action to try to get bin Laden before the Sept. 11 attacks.
The Clinton administration did strike targets in Sudan and Afghanistan following attacks on U.S. embassies in Africa. Bin Laden was not hit, and may have been tipped off by a former head of Pakistani intelligence, Hamid Gul.
The report said officials in both the Clinton and Bush administrations, feared a failed attempt on bin Laden could kill innocents, boost bin Laden's prestige and lacked public support.
It wasn't until the day before the attacks that second-tier Bush Cabinet officials settled on a three-phase strategy: talks with the Taliban, followed if necessary by covert support for anti-Taliban fighters and, if those failed, direct military action.
At Tuesday's hearing, Secretary of State Colin Powell strongly defended the administration's efforts.
Powell said that even if U.S. forces had invaded Afghanistan, killed bin Laden and neutralized al Qaeda, "I have no reason to believe that would have caused them to abort their plans."
At least one Sept. 11 survivor agreed.
"He has a following where these men are willing to die for their cause. And they multiply by the thousands every hour," William Rodriguez, who was at the World Trade Center, told the CBS News Early Show.