-- The Bush administration says it's "ramping up" America's terror defenses ahead of some upcoming events that could be al-Qaida targets.
But White House Press Secretary Scott McClellan acknowledges there's been no spike in terrorist "chatter" monitored by U-S intelligence.
Rather, he says there's been a "continuous stream" indicating al-Qaida has operatives in America who may be plotting to strike.
He points to Saturday's dedication of the World War Two memorial in Washington, the upcoming G-Eight summit in Georgia, the Fourth of July and the summer political conventions as "possible targets."
McClellan says Americans should be vigilant -- because the nation "is in a serious threat period."