DETAILS OF TERROR PLOT COME TO LIGHT…. Throughout the day yesterday, there were reports on a potential terrorist threat targeting the U.S., but the accounts were at best incomplete, and at times, contradictory.

Yesterday afternoon, the White House briefed the media on the details of what we know so far, and what President Obama characterized as a “credible terrorist threat” to the United States.

Officials searched for suspicious packages in the United States and other countries after two shipments containing explosives, sent from Yemen and addressed to synagogues in Chicago, were intercepted in Britain and Dubai.

The discovery of the explosives packed in toner cartridges for computer printers, based on a tip from Saudi intelligence officials, set off a broad terrorism scare on Friday that included the scrambling of fighter jets to accompany a passenger flight as it landed safely in New York.

Cargo planes were moved to secure areas of airports in Philadelphia and Newark for searches, and a United Parcel Service truck in Brooklyn was stopped and inspected. No additional explosives had been discovered by early Saturday morning.

Representative Jane Harman, a California Democrat on the House Homeland Security Committee, said Friday that the packages seized in Britain and Dubai contained PETN, the same chemical explosive contained in the bomb sewn into the underwear of the Nigerian man who tried to blow up an airliner over Detroit last Dec. 25. That plot, too, was hatched in Yemen, a country that is regarded as one of the most significant fronts in the battle with extremists.

It’s likely more information will yet come to light, but based on reports this morning, the explosive was put in computer printer cartridges. We do not yet know how the explosives were intended to be activated.

The U.S. government was alerted to the shipment by intelligence officials in Saudi Arabia, who closely monitor radicals in Yemen — where plots against Saudis are not uncommon — and who were able to give U.S. officials detailed information about the threat.

And before anyone starts talking about the need to invade Yemen, it’s worth emphasizing that Yemeni officials are reportedly “working closely with the United States and other countries to assess the episode,” and John Brennan, the president’s top counterterrorism adviser, offered public praise for Yemen’s cooperation.

As for the politics of all of this, Republicans are not yet whining or trying to exploit the threat for partisan gain — the day is young — and Rep. Peter King (R-N.Y.), the ranking Republican on the Homeland Security Committee, conceded late yesterday, “So far everything has worked the right way.”

I can only assume Liz Cheney and Rudy Giuliani will be along soon to argue otherwise.

In any case, while these explosives have been found, U.S. officials continue to search for other possible packages, just in case. “We don’t want to presume we know the bounds of this plot, so we are looking at all packages,” Brennan said.

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Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.