Some of the intelligence "chatter" that led President Bush to put the nation on high "orange" alert for a terrorist strike dealt with threats against remote facilities, according to law enforcement and intelligence officials speaking Tuesday on condition of anonymity.
One specific threat, they said, was against oil facilities in Valdez, Alaska, where tankers load Prudhoe Bay oil destined for the continental United States. Other threats are more general, mentioning nuclear plants in rural areas and other electric facilities, major dams, bridges or chemical plants, the officials said.
U.S. intelligence officials have heard all these threats before, but never in this volume and with this much credibility, reports CBS News National Security Correspondent David Martin. What makes the threats so credible, these officials say, is that both U.S. and British intelligence simultaneously and independently picked up essentially the same information from different sources.
The two streams of intelligence reporting came together last Friday and by Sunday the U.S. had raised the terror threat alert, among other things increasing air patrols over major cities and positioning anti-aircraft missile batteries around Washington, D.C.
"We're taking this threat very seriously and putting into place several added security measures," said Gen. Richard Myers, chairman of the Joint Chiefs of Staff.
Other intelligence points to possible attacks in cities such as New York, Washington or Los Angeles, which have been targeted by terrorists before. Aircraft continue to be a favored al Qaeda method, particularly aircraft originating from overseas and those carrying cargo — both of which have less security than U.S. passenger aircraft.
Officials say there also seems to be interest in targeting holiday events that draw large crowds, such as college and professional football games and New Year's celebrations and parades.
Americans across the nation are likely to notice increased air patrols as the government continues its response to Sunday's decision to raise the nation's terror threat level to orange, or high, the second-highest point, the Defense Department said. It marked the fifth time the level has gone above yellow, or elevated, since the five-point system was developed after the Sept. 11, 2001 terror attacks.
Patrols of warplanes will increase "over select cities and facilities" in the coming days, said Myers, adding that air defenses were put on higher alert in the Washington area and also at "different air bases throughout the country."
Government officials continued to convey a sense of guarded urgency about the latest terror threats, which have been described as the most serious since the Sept. 11 attacks.
Defense Secretary Donald H. Rumsfeld said the government acted appropriately in raising the terror risk level given the volume and nature of intelligence.
"You do not do it lightly," Rumsfeld said. "You ask, 'Is it serious?' Yes, you bet your life'."
Security continued to tighten at the nation's airports, with more bomb-sniffing dogs in visible use, parking restrictions in force and baggage screeners taking extra care. Additional officers have been activated along the U.S.-Canada border.
Overseas, the U.S. suspects terrorists are eyeing Saudi Arabia, Kenya, Bahrain, Yemen and Turkey for attacks during the Christmas and yearend holiday season.
Bahrain, which hosts the base of the U.S. Navy's 5th fleet and is experimenting with democratic elections, was singled out specifically through a message by the U.S. Embassy in Manama to U.S. citizens in the Gulf country.
Americans were advised to stay away from places where Westerners congregate and to reduce unnecessary travel.
Officials in Turkey said they fear militants may be preparing to organize new attacks on American, Israeli and other Western interests or on Istanbul's most popular shopping mall.
State Department spokesman Richard Boucher said American embassies regularly re-examine their operations to see what can be done to increase security when alerts are high.
"They look at things like access routes, police presence, whether there are other things we need to ask the local governments for," such as closing roads, he said.