<p>Big one U.S. intelligence officials say there are signs terrorists are planning a major attack during the holiday season. But the signs are not specific enough to issue a warning to the public. Increased chatter among terrorist groups associated with the al Qaeda network has been a common indicator in the past. Intelligence agencies have been picking up signals since early December from terrorist suspects indicating that an attack is being planned. "They are talking about 'the big one,'" an intelligence official tells us. U.S. government public warnings about terrorism over the Christmas and New Year's holiday have been limited to overseas-travel advisories. The latest intelligence says a major terror attack could be carried out in the United States, the officials said. The FBI warned this week that terrorists may attempt to blow up an airliner using explosives-laden shoes, similar to the attempt a year ago by accused shoe-bomb suspect Richard C. Reid. CIA Director George J. Tenet said in a recent speech that the al Qaeda network is preparing terrorist attacks. He noted that recent taped messages by al Qaeda leaders were "unprecedented in their bluntness and urgency."</p>
