President Bush, warning Americans Wednesday that "terrorists are still active ... and still trying to kill our people," announced the transfer of 14 key terrorist suspects from secret CIA custody to the U.S. Naval base at Guantanamo Bay, Cuba, including alleged Sept. 11 mastermind Khalid Sheik Mohammed.
He also announced that he was asking Congress to pass legislation that would allow the United States to try the terror suspects for war crimes.
"The families of the 9/11 attacks have waited patiently for justice," Bush said.
• Raw Data: List of 14 Terror Suspects
Issuing a warning to terrorists around the world, the president added, "We will find you, and we will bring you to justice."
The president's comments came during a White House speech on the War on Terror, his third such speech, and before an audience of Sept. 11 families and first responders.
Bush acknowledged for the first time the existence of secret prisons to hold terrorist suspects and outlined how the CIA and the government's intelligence and law enforcement agencies were fighting a secret war against Al Qaeda to "stop attacks before they occur."
He detailed how the administration plans to legally try the more than 400 detainees held at Guantanamo Bay. The suspects will be transferred to Defense Department custody as a first step in preparing them for trial, a senior administration official. The suspects would be afforded some legal protections consistent with the Geneva Conventions, he said.
In addition to Sheik Mohammed, believed to be the No. 3 Al Qaeda leader before his capture in Pakistan in 2003, the suspects include: Ramzi Binalshibh, an alleged would-be Sept. 11 hijacker, and Abu Zubaydah, whom U.S. intelligence officials believe was a key link between Usama bin Laden and many Al Qaeda cells. Zubaydah was captured in Pakistan in March 2002.
The announcement of the prisoner transfers is the first time the administration has acknowledged the existence of CIA prisons, which had been reported in the media and the subject of friction between Washington and some allies in Europe. The administration has come under criticism for its treatment of terrorism detainees.
Bush referred to his comments on the CIA program as "limited disclosures" to enable intelligence officials to continue to investigate terrorists' knowledge of future attacks.
"To win the War on Terror, we must be able to detain, question and when appropriate, prosecute terrorists captured here in American and in battlefields around the world," Bush said.
The disclosure of initial leads, photographic identification, voices in recordings of intercepted calls and interpretation of terrorism communications have allowed U.S. officials to stop attacks against the United States, Bush said.
It also came as the president pressed a hard line with Congress on legislation he says is needed to permit the trial of terror suspects through military tribunals. Bush exhorted lawmakers on Wednesday to allow evidence to be withheld from a defendant, if necessary, to protect classified information.
"One of the most important tasks is for Congress to recognize that we need the tools necessary to win this War on Terror and we'll continue to discuss with Congress ways to make sure that this nation is capable of defending herself," Bush said after meeting with members of his Cabinet.
The Supreme Court ruled in June that military tribunals were never authorized by Congress and would violate U.S. and international law. Since the ruling, administration officials have been working on a new proposal to try terrorism suspects.
Of the 770 terror suspects had been sent to Guantanamo Bay, 315 of were returned to other countries and 455 remain in U.S. custody, Bush said.
Some of those suspects are linked to the 2000 bombing of the USS Cole in Yemen and the 1998 attacks on U.S. embassies in Kenya and Tanzania.
Bush's 40-minute speech pressured Congress to pass legislation that would allow military trials for terror suspects so they "can face justice."
Sen. John Warner, R-Va., chairman of the Armed Services Committee, said Congress will come to a resolution.
"Obviously there will be differences in approach by the administration and the Congress," Warner said.
Warner, Sens. John McCain and Lindsey Graham drafted a proposal different than the White House measure that would guarantee legal rights to defendants and access to evidence used against them.
"I think it's important that we stand by 200 years of legal precedents concerning classified information because the defendant should have a right to know what evidence is being used," McCain said.
White House spokesman Tony Snow downplayed reports that there are major differences between the White House and Congress.
"It's going to get worked out," Snow said when asked if the White House will negotiate with the lawmakers. "It may be that the Hill is willing to negotiate."
Bush's proposal faces opposition from members of Congress, including Republicans, over objections to whether prosecutors could use sensitive evidence that defendants would not be allowed to see. Some Republicans say it is violates constitutional rights of due process and could encourage other countries to use the same procedure against captured U.S. military personnel.
Some military lawyers back a system similar to the current system of military courts martial. Attorney General Alberto Gonzales has objected to rules that would give terror suspects the right to remain silent or challenge hearsay evidence.
Senate Majority Leader Bill Frist, R-Tenn., said he will likely introduce the legislation late Wednesday.
The president also is scheduled to meet with members of his Cabinet and Republican leaders Wednesday. The White House plans a fourth speech by the president in the series on the War on Terror Thursday in Atlanta.
The president's speech comes a day after proclaiming that the United States "will not retreat" from the fights against radical Islamists bent on attacking America.
"We will not rest, we will not retreat, we will not withdraw from the fight until this threat to civilization is removed," Bush told a gathering Tuesday of the Military Officers Association of America.
The speeches lead up to Bush's trip to New York on Monday's fifth anniversary of the Sept. 11, 2001, attacks. Bush will visit ground zero, the Pentagon and the Pennsylvania field where Flight 93 passengers forced hijackers to crash to avoid further loss of life.
FOX News' Wendell Goler and The Associated Press contributed to this report.