All information is preliminary, but media are reporting that a would-be suicide bomber was arrested on his way to the U.S. Capitol today. According to Politico:

A Moroccan man suspected of plotting a suicide attack at the Capitol was arrested Friday near the building, according to the U.S. Capitol Police and media reports.
“This arrest was the culmination of a lengthy and extensive operation during which the individual was closely and carefully monitored,” spokeswoman Kimberly Schneider said in a statement. “The U.S. Capitol Police was intimately involved in the investigation for the duration of the operation. At no time was the public or Congressional community in any danger.”

Fox News says the would-be suicide bomber thought he was wearing a vest filled with live explosives, but that the ordnance was actually inert:

The man thought undercover FBI agents assisting him in his plot were associates of Al Qaeda. …When he was arrested Friday in Washington, he was carrying with him a vest supposedly packed with explosives, but the material inside was not actually dangerous, Fox News was told.

A short time earlier, he had been praying at a mosque in the Washington area. His destination was Capitol Hill.

The public was never in danger, as he had been under constant surveillance for some time, officials said.
In a statement that did not get into the details of the alleged plot, the U.S. Capitol Police said the suspect was “closely and carefully monitored.” Capitol Police confirmed the suspect was arrested on Friday.

“At no time was the public or congressional community in any danger,” the department said.

A senior source involved with law enforcement at the Capitol also told Fox News the investigation was “all very controlled.” The source said the U.S. Capitol Police was involved with the FBI and other agencies in tracking the suspect “not more than a year.”

More from WaPo:

The Moroccan man entered the United States with a family member, and at some point, he came to the attention of the FBI, said a law enforcement official.

Undercover FBI agents gave the man inoperable explosives and a gun, and he was followed Friday into the District, said the official, who spoke on condition of anonymity because the investigation is ongoing.

The man was arrested in a parking lot near the Labor Department, which is just a few blocks from the Capitol, the man’s apparent target, according to the official.

Kudos to the FBI for another successful sting operation, and another attack prevented (though we should be prepared, again, for recriminations from some corners, including the claim that undercover FBI assets “assisting” the suspect may have pushed him farther along in the process of planning and executing an attack than he would have gone without their assistance and encouragement [UPDATE:I told you so]).

Predictably, the media can’t make up their minds whether this would-be bomber was a “lone wolf,” a term which has become incredibly over- and mis-used in discussions about would-be terrorists.  The AP ups the absurdity quotient by claiming that the suspect “was not believed to have any known connections to al Qaeda,” given the fact that, as noted above, “the man thought undercover FBI agents assisting him in his plot were associates of Al Qaeda” (emphasis added).

More on this as it develops.