HIGHLIGHTS: Planned Attack as Big or Bigger Than Sep. Attacks||Intercepted Messages Deliberately Vague To Leave US Concerned Officials Uncertain About Timing||Use of Chemical or Biological or Nuclear Weapons Feared||STORY:
U.S. officials have detected "enhanced activity of concern" in intelligence gathered in recent weeks and months about a possible new attack against the United States or U.S. interests abroad, a White House official said on Saturday. (Read photo caption)

The comments by the official, who asked not to be quoted by name, came as The New York Times reported on its Web site that U.S. intelligence agencies have intercepted a series of messages among al Qaeda operatives indicating that Osama bin Laden's network is attempting to carry out an attack as big as or bigger than the one on September 11.

Quoting unidentified intelligence and law enforcement officials, the Times characterised the communications as vague but disturbing. The intercepted messages are so general that they have left President George W. Bush and U.S. counter-terrorism officials uncertain about the timing, location or method in this potential attack, the Times reported.

Officials cited by the Times said the intercepted messages represent some of the most credible intelligence gathered since the September 11 attacks on al Qaeda's future plans.

U.S. intelligence agencies have gathered reports of potential threats to U.S. interests by al Qaeda continuously since September 11 and continue to be worried about another potential attack, an intelligence official who requested anonymity told Reuters.

WEAPONS OF MASS DESTRUCTION?

The Times said communications referring to possible mass casualties do not specifically mention the use of weapons of mass destruction such as chemical, biological or nuclear weapons.

Bush has faced criticism in recent days over disclosures that a series of possible clues about al Qaeda's plans went unheeded in the months before the September 11 attacks.

U.S. Senate Intelligence Committee Vice Chairman Richard Shelby said on Saturday the FBI had "failed the American people" in its handling of key information about potential attacks prior to September 11.

PHOTO CAPTION

New York's World Trade Center collapses on September 11 2001. REUTERS/Reuters TV