By Steve Holland

CRAWFORD, Texas (Reuters) - President George W. Bush was told a month before Sept. 11, 2001, that al Qaeda members were in the United States and the FBI had detected suspicious activity "consistent with preparations for hijackings or other types of attacks," according to a secret memo the White House released under pressure on Saturday.

White House officials were quick to say after the document's evening release that the Aug. 6, 2001, memo did not warn of the Sept. 11 attacks and that although it referred to the possibility of hijackings, it did not discuss the possible use of planes as weapons.

"There's nothing in here that we can show was tied to the 9/11 plot," a senior White House official told reporters.

But the President's page-and-a-half Daily Brief, entitled "Bin Laden Determined to Strike Inside the U.S.," was likely to intensify the election-year debate in Washington over whether the Sept. 11 attacks could have been prevented in spite of Bush's insistence the U.S. government did everything it could to head them off with the information on hand.

It was released at a time when Bus is already under political pressure over mounting U.S. casualties in Iraq.

"SUSPICIOUS ACTIVITY"

The report said it had not been able to corroborate some of the "more sensational threat reporting," such as one in 1998 that Osama bin Laden wanted to hijack a U.S. aircraft to gain the release of those responsible for the 1993 bombing at the World Trade Center.

But the document said the FBI since then had detected "patterns of suspicious activity in this country consistent with preparations for hijackings or other types of attacks, including recent surveillance of federal buildings in New York."

A White House fact sheet released along with the secret document attempted to play down this potentially explosive disclosure. It said the information relating to the possible surveillance of federal buildings in New York was later determined by the FBI to be "consistent with tourist-related activity."

And it said the document otherwise contained no information from FBI investigations that indicated activities related to the preparation or planning for hijackings or other attacks within the United States.

The declassified report said al Qaeda members, including some U.S. citizens, "have resided in or travelled to the US for years, and the group apparently maintains a support structure that could aid attacks."

"A clandestine source said in 1998 that a Bin Ladin (sic) cell in New York was recruiting Muslim-American youth for attacks," it said.

The White House official said the memo on Bin Laden was prepared in response to a question by the president about the extent of the al Qaeda threat domestically. Bush had inquired earlier after seeing intelligence reports about possible al Qaeda threats to U.S. targets overseas.

It told the president of desires by bin Laden to "bring the fighting to America" dating to 1997 and that he wanted to retaliate "in Washington" over the 1998 cruise missile strikes against his base in Afghanistan.

It was highly unusual for the U.S. government to make public a sensitive presidential intelligence memo. Three redactions were made from it to protect the names of foreign governments that provided information to the CIA.

The release of the memo had been demanded by members of the commission investigating the 9/11 attacks, and Democrats on the commission who had already seen it had questioned whether Bush could have done more to stop the attacks.

National security adviser Condoleezza Rice insisted in her public testimony to the 9/11 commission last week that the memo contained mostly historical information and did not warn of any coming attacks inside the United States.

ATTACK WITH EXPLOSIVES

Her account could be contradicted by the fact that the memo included information from three months beforehand that al Qaeda members were trying to enter the United States for an attack with explosives.

"The FBI is conducting approximately 70 full field investigations throughout the U.S. that it considers Bin Laden-related. CIA and the FBI are investigating a call to our Embassy in the UAE (United Arab Emirates) in May saying that a group or Bin Laden supporters was in the U.S. planning attacks with explosives," the document said.

That part of the document could set up a Washington blame game over whether the FBI was adequately doing its job.

The document gave neither a time nor a suspected target for such an attack with explosives.