From Fox News report:
On Monday, the Arabic-language newspaper Al-Hayat ran a story saying a communiqué attributed to Al Qaeda claimed responsibility for the blackout, saying that "the brigades of Abu Fahes Al Masri" had hit two main power plants supplying the eastern region of the United States and major U.S. and Canadian industrial cities.
The communiqué, reportedly posted on the Web site of the International Islamic Media Center (search) and translated by the Middle East Media Research Institute (search), assured that the operation "was carried out on the orders of Usama bin Laden to hit the pillars of the U.S. economy," as "a realization of bin Laden's promise to offer the Iraqi people a present."
The communiqué also said: "Let the criminal Bush and his gang know that the punishment is the result of the action ... the Americans lived a black day they will never forget.
"They lived a day of terror and fear ... a state of chaos and confusion where looting and pillaging rampaged the cities, just like the capital of the caliphate Baghdad, and Afghanistan and Palestine were. Let the American people take a sip from the same glass."
The statement outlined certain conditions Al Qaeda purportedly wanted met, including the release of all detainees held by the U.S. and for non-Muslim powers to leave the "land of the Muslims, including Jerusalem and Kashmir."
It noted that the event shut down nine nuclear reactors in New York, New Jersey, Ohio and Michigan and brought public transportation and banking transactions to a halt.
"We tell the people of Afghanistan and Kashmir that the gift of Sheikh Usama bin Laden is on its way to the White House."
High-ranking U.S. officials basically laughed at the idea Al Qaeda could be behind the blackout.
"I would take that one with a huge grain of salt," one official told Fox News.
The source added that there had been no indication, domestically or internationally, that Al Qaeda or anyone else intentionally triggered the power-grid collapse.
"It's probably a good PR stunt to put the idea out there that [Al Qaeda] could do that," terrorism expert Harvey Kushner told Fox News. "Certainly they're interested in having this type of capability, but they prefer, most certainly, a low-tech type of truck bombs, flying planes into buildings. They don't have this type of sophistication."
"Quite frankly," Kushner added, "I wouldn't lose any sleep from the possibility they could take down power grids and things like that."