This official described the chatter as "terrorist electronic and internet intercepts" some of which are in the form of morale booster messages like, "Stay tuned. Good news is on the way." Some suggest "targets in the United States;" others say "overseas."
Much of the increased chatter is taking place in Afghanistan and began to spike in volume earlier this week. They suggest an impending attack against the U.S. and its allies both in America and overseas but contain no specifics.
It may possibly be related to the Sept. 9 anniversary of the assasination in Afghanistan of a Northern Alliance leader.
The threat is "non-specific" and officials say the increased communications is "less intense" than a spike that occurred around July 4, but that it is still "intense."
"It is similar but not quite as serious" as the chatter picked up around last July 4, said one official.
It was enough, however, for the Pentagon to immediately resume 24-hour a day Combat Air Patrol over Washington and New York, something they hadn't planned on doing until next week's 9-11 anniversary. The patrols will continue indefinitely.
In addition, the U.S. embassy in Kabul, Afghanistan has been "buttoned up."
In a related development, German authorities said Friday they arrested a Turkish man and his fiancee, a civilian employee of the U.S. military, who are suspected of planning an attack on a U.S. military installation.
The couple had 287 pounds of chemicals and five pipe bombs at the time of their arrest Thursday in an apartment near Heidelberg, where the U.S. Army Europe is headquartered.
"We suspect that they intended to mount a bomb attack against military installations and the city of Heidelberg," the chief law enforcement officer for Baden-Wuerttemberg state, Thomas Schauble told reporters.
The 25-year-old man appeared to be a follower of Osama bin Laden, and was a strict Muslim "who hates Americans and Jews," Schauble said.
His 23-year-old fiancee worked at a supermarket at a U.S. installation in Heidelberg and holds joint German-American citizenship. The man worked at a chemical warehouse in nearby Karlsruhe. They were arrested in their apartment in Walldorf, about six miles south of Heidelberg.
No official has made a connection between the German arrests and the increased chatter within Al Qaeda but the timing is certainly suspicious.
Since the Sept. 11 attacks, law enforcement authorities have instituted a plethora of tightened security measures, including more stringent inspections at U.S. borders and increased screening at airports. A proposed Homeland Security department which would reorganize the president's cabinet to tighten security and information sharing is currently being debated by Congress.
For the one-year anniversary of Sept. 11, the government is imposing flight restrictions over the airspace where planes went down last September. The temporary rules will cover the three sites where hijacked planes crashed that day. They'll coincide with public ceremonies in New York, Washington and the Somerset County, Pennsylvania, field where Flight 93 went down.
Long-term security measures include: