Sources: Major terror attack possible this summer
From Kelli Arena
CNN Washington Bureau
(CNN) -- Several U.S. officials said Tuesday that intelligence indicates there is increasing concern about the possibility of a major terrorist attack on U.S. soil, perhaps as early as this summer.
Such an attack might take place before the November presidential election in an attempt to affect the outcome, the officials said.
For weeks, security officials have expressed concern about several upcoming high-profile events, including Saturday's dedication of the National World War II Memorial on the National Mall in Washington, D.C.
Other potential targets include the G8 economic summit on Sea Island, Georgia, Fourth of July celebrations, the Democratic convention in Boston, the Republican convention in New York, and the Olympics in Greece.
Although there is no specific target, time or date for the possible attack, the information is the culmination of intelligence that has been known and gathered over time -- and it is the assessment that is new, the sources said.
The FBI is likely to issue alerts for several individuals the bureau would like to locate in the coming days, two counterterrorism sources told CNN.
The sources would not describe who those persons are and why they are wanted now. One source said the bureau would be re-issuing alerts for some people already wanted.
CNN has learned there is no plan to raise the terror threat level, which is at yellow, or elevated.
New York Police Commissioner Raymond Kelly said his department had received "highly sensitive intelligence" as recently as Tuesday, and there was "nothing in that reporting to indicate a specific threat or looming attack against New York City.
"Nor have we been advised that terrorists are known to be in the United States actively plotting such an attack," Kelly said in a statement.
The Los Angeles and Boston police departments made similar comments.
An official with the Department of Homeland Security said the agency remains concerned about the general al Qaeda threat but had no new specific information.
"We are not aware of any new highly credible intelligence indicating a planned attack in the U.S. this summer," the official said. She added: "Nothing in the current intelligence is exceptionally specific."
The FBI is expected to give guidance to its 18,000 state and local law enforcement partners in the regular weekly FBI bulletin Wednesday.
FBI Director Robert Mueller and Attorney General John Ashcroft will hold a news conference Wednesday to discuss their commitment to disrupting potential plots, CNN has learned.
Officials said security will be unprecedented for World War II Memorial dedication Saturday. More than 140,000 people, many of them elderly, are expected for the event. (Full story)
More than 35 federal, state and local agencies have been involved in planning for the event for a year now. Some 1,000 law enforcement officers are expected to be on hand in addition to special support and response teams.
Following the March 11 train bombings in Madrid, Spain, security officials have expressed concern that so-called "soft targets" such as passenger and freight trains could be vulnerable to attack in the United States.
Homeland Security Secretary Tom Ridge announced a series of initiatives to improve train and subway security shortly after the bombings.
The national terror threat alert level was raised to orange, or high, during the holiday season last December and January. It has been at yellow since January 9.
Before that, the United States last raised the domestic terrorism threat level to orange May 20, 2003, after suicide bombings in Saudi Arabia and Morocco that were blamed on al Qaeda. That alert lasted 10 days before the threat level was returned to yellow.
Other orange alerts were raised in 2002 around the first anniversary of the September 11 attacks and in February 2003, on the eve of the U.S.-led invasion of Iraq in March.