The Fourth of July is an attractive symbol to potential terrorists and Americans should take extra care on the national holiday, Secretary of State Colin Powell said Sunday.

"There have been a variety of ... intelligence reports that suggest we ought to be especially vigilant as we go into the Fourth of July season," Powell said.

The FBI plans to monitor and protect major Independence Day parades and festivities as a precaution against an attack. The bureau also has issued a law enforcement bulletin asking police to be on heightened alert even though no specific new intelligence suggests an attack.

The bureau chose not to make the warning public since it was vague and there are fears Americans might be suffering from "threat fatigue" after a series of nonspecific warnings in past months, The New York Times reported.

"The FBI possesses no information indicating a specific and credible terrorist threat related to the July 4 Independence Day time frame," the newspaper said the agency wrote in a message relayed on Wednesday.

"In the course of the next couple of days, we'll be meeting on a regular basis to make an assessment of any additional threats that might be coming our way," Powell said on CBS' Face the Nation.

"But I hope most Americans will go about their business and enjoy the Fourth of July. I intend to."

The president's national security adviser, Condoleezza Rice, said on CNN's Late Edition that "a lot of preparations are being made ... to try and secure obvious sites and the like."

She said Americans must realize this is the first Independence Day since the Sept. 11 attacks.

"Certainly the Fourth of July just symbolically is an important day," Rice said on NBC's Meet the Press.

"It is a time for enhanced vigilance, and we ask the help of the American people in that way."

The information about a threat is not specific, Powell said, but rather "the usual body of information and intelligence that comes forward."

He said the FBI, CIA and other agencies on the federal, state and local levels "are examining all of this carefully so that we can make sure that we are on alert but, at the same time, make sure that the American people can enjoy our national holiday."

The Associated Press contributed to this report.