The American airforce subsequently traded the high-explosive bombs carried by its B-29s for incendiaries.

ECONOMIST: Japanese history

Mr. JOEL KAPLAN (White House Office of Management and Business): We will provide additional funding for new resources to protect our troops against roadside bombs and makeshift, improvised explosive devices that have been a major source of casualties.

NPR: Bush Promotes Competitiveness Initiative

No matter how you slice and dice the numbers that are out there, whether you include, clearly sectarian car bombs and IED - improvised explosive devices - no matter what it is, it has come down by about two-thirds since December last year.

NPR: Petraeus Faces 'Complex' Demands in Iraq

For one thing, they say they're getting better at detecting the bombs, which the Pentagon calls IEDs, for improvised explosive devices.

NPR: Bush Speech Highlights the Challenge of the Iraqi Insurgency

The FBI's bomb experts analyzed remnants of both bombs that exploded on April 15 near the marathon's finish line, as well as additional explosive devices that authorities said were recovered after the encounter with the suspects early on April 19.

WSJ: FBI Says Boston Bombs Suggest Expertise