2 Planes Diverted After Disturbances

Sept. 11, 2002 -- With the nation on heightened alert for terrorist attacks today, observances of the Sept. 11 anniversary passed smoothly, but officials reported a handful of incidents around the country.

American Airlines Flight 1702 returned to Houston's George Bush Intercontinental Airport shortly after takeoff because a flight attendant reported seeing a passenger with a small folding knife. Two air marshals aboard the plane responded and the man was removed after it landed, officials told ABCNEWS.

The Dallas-bound plane, which was carrying 50 passengers and a crew of four, received a fighter jet escort as it turned around.

Further investigation determined the passenger in fact did not have a weapon, officials said. What he had been holding turned out to be a folding comb.

The FBI said officials questioned another man aboard the plane who aroused fellow passengers' suspicions by changing seats during the flight. No charges were filed against either of the men on the Dallas-bound flight.

In a separate incident, a Northwest Airlines jetliner traveling from Memphis, Tenn., to Las Vegas was diverted to Fort Smith, Ark., after the crew reported that four men acted suspiciously during the flight and refused to obey orders from the five-member cabin crew.

"Some of the crew members became suspicious because of some of the actions taken by the four subjects," said Sgt. Jarrard Copeland of the Fort Smith Police Department. At least three of the men locked themselves in a bathroom, and some passengers reported they might have been trying to shave themselves.

"[One of the men was] walking up and down, and the stewardess asked him again to sit down, and he went to the back and that's the last I saw of him," said passenger Cathy McDougal, of Long Beach, Miss.

"The next thing you know, the pilot came on and said that we were making an emergency landing and we went down real fast," McDougal said.

All 94 passengers were taken off Flight 979 without problems and the men were brought into a hangar and then removed from the airport.

The FBI determined there was no criminal activity aboard the plane.

In Columbus, Ohio, a 42-story building housing numerous government offices was evacuated after dogs detected the scent of explosives. No explosives were immediately found, but police took one man into custody, officials told The Associated Press.

High Alert for Terrorist Attacks

On Tuesday, the Bush administration elevated the color-coded terrorist threat level from yellow to orange — the second-highest alert level — and warned of a high risk of terrorist attacks in the coming days.

The heightened alert marked the first raise since the system was implemented in March and was based on what Attorney General John Ashcroft called "specific intelligence on specific attacks on U.S. interests overseas."

"We believe this to be credible information and the analysis that has been taken by intelligence agencies leads us to believe this is an appropriate step," Ashcroft said Tuesday during a news conference with Director of Homeland Security Tom Ridge.

The recommendation for the move to a new level was made by various federal law enforcement and security agencies, and approved by President Bush, who said the threats were reminiscent of those detected before last year's attack.

Al Qaeda Prisoner Described New Attack Plans

Intelligence sources told ABCNEWS some information about a possible attack in Asia came from a "second-level" al Qaeda operative in U.S. custody who only recently began cooperating with American officials. Evidence suggested that terrorists had been planning car-bomb or other attacks on U.S. facilities in Southeast Asia, and had been accumulating explosives since January of this year, officials said.

He told officials the terror group was planning an attack on U.S. targets around Sept. 11 this year, officials said.

Intelligence sources identified the informant to ABCNEWS as Omar al-Farouq, whom they described as al Qaeda's station chief for Southeast Asia, overseeing tactical and financial operations for the region.

Al-Farouq ranks below Abu Zubaydah, a top al Qaeda leader captured by U.S. forces in March, who has been the source of previous warnings about potential attacks.

Sources told ABCNEWS al-Farouq had direct dealings with Khalid Sheik Mohammed, a top leader of the terror network along with Zubaydah. Mohammed remains at large.

Al-Farouq's information was considered credible because some of his other claims had been independently verified. Some claims were also corroborated with another al Qaeda detainee, sources said.

Al-Farouq was captured in June in Indonesia on the island of Java. He began cooperating with U.S. authorities in recent weeks, and sometime between Sunday and Monday he gave the details about a series of overseas attacks set to coincide with the Sept. 11 anniversary, sources said.

U.S. officials also had indications that terrorists in the Middle East were preparing for a suicide attack on U.S. targets at unknown locations. Law enforcement sources told ABCNEWS that officials' greatest concern was the possibility that al Qaeda sympathizers and sleeper cells would attack on their own, without direction from senior al Qaeda leadership.

Symbols of U.S. Power Likely Targets

Ashcroft said Tuesday there was also evidence that terrorists could be plotting attacks inside the United States, but said there was "no evidence of an imminent attack at home."

He said that the most likely targets were the transportation and energy sectors, and symbols of American power, such as military facilities, embassies and national monuments.

"Lower-level al Qaeda operations may view the Sept. 11 anniversary as a suitable time to lash out" in small, less sophisticated attacks against U.S. targets, he said.

The information behind the heightened alert was corroborated by multiple intelligence sources, Ashcroft said.

Ridge recommended Americans take "common-sense precautions" over the coming days, but urged them not to cancel travel plans or avoid remembrance ceremonies marking the anniversary of last year's attacks.

Live Missiles Mounted Around the Capital

The heightened alert came amid a flurry of increased security measures in the United States and abroad in the days leading up to the anniversary of last year's terror attacks. These included:

The White House decided Tuesday to put live anti-aircraft missiles with the air defense units in and around the Washington, D.C., area. One defense official said the decision to arm the units was not a response to a specific threat but a precaution to improve radar and air defense around the region. The missile batteries, mounted atop Humvees, were originally supposed to be part of a defense exercise only.

All air marshals — believed to number between 2,000 and 6,000 — will be on duty over the next few days, transportation officials told ABCNEWS. The Coast Guard is also increasing patrols over the next few days.

The U.S. military expanded fighter jet patrols over about 10 cities.

Ridge called state and local officials to explain the new threat, and advise increased visibility of law enforcement at today's events.

Worldwide Precaution

In addition, U.S. military forces in Bahrain Tuesday were put on the highest alert — Condition Delta — based on "credible" but not specific threats there, and the State Department issued a worldwide caution urging Americans to remain especially vigilant.

The U.S. Central Command, based in Tampa, Fla., raised its Force Protection Condition to Delta today. Military facility security ranges from normal to Alpha, then Beta, Charlie, and finally Delta, the highest condition.

Approximately 15 embassies or diplomatic posts were closed today due to security concerns. State Department spokesman Richard Boucher said the list would change as new information was evaluated.

U.S. officials warned the Philippines of an al Qaeda plot to attack U.S. embassies withtruck bombs some time around the September 11 anniversary, officials there said.

The U.S. embassies in Malaysia and Indonesia have closed indefinitely, and the U.S. diplomatic mission in Cambodia has been shut down for three days as a precaution, according to The Associated Press. Thailand's prime minister, Thaksin Shinawatra, said he would increase security at U.S. diplomatic offices there, also as a precaution.

ABCNEWS' Jackie Judd, Pierre Thomas, Lisa Stark, John McWethy and Terry Moran contributed to this report.