Tim Cook tells NBC Apple will be building Macs in the U.S.

Tim Cook drops a bombshell in his interview with Brian Williams scheduled to air Thursday evening: Apple (AAPL) next year will begin manufacturing one of its existing Mac lines exclusively in the U.S.

The news came in a NBC releaseposted early Thursday morning. "We've been working for years on doing more and more in the United States," Cook tells Williams in a Rock Center broadcast scheduled for 10 p.m. Eastern. The NBC video.

Apple shipped the vast majority of its manufacturing to China shortly after Cook joined Apple from Compaq. He didn't specify which line of Macs would be made in the U.S., but reports last weekthat some of the new 21-inch iMacs come with "Assembled in the USA" labels on them is strongly suggestive. (Note, however, that soldering in a few parts in an iMac is not the same as building an entirely new manufacturing plant.)

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In an interview with Bloomberg Businessweek released the same morning, Cook offers a bit more detail. He tells editor Josh Tyrangiel that the company plans to spend more than $100 million next year to shift assembly from Foxconn's Chinese plants to facilities in the U.S. "This doesn't mean that Apple will do it ourselves," he says, "but we'll be working with people and we'll be investing our money."

"I don't think we have a responsibility to create a certain kind of job," Cook added. "But I think we do have a responsibility to create jobs."

Although nearly every U.S. electronics company relies on Foxconn to assemble its products, it's Apple that usually takes the heat in press stories about the practice. The New York Times has been particularly critical of Apple both for shipping American jobs overseas and for turning a blind eye on working conditions in those overseas plants.

The Times was not included in what was, with the simultaneous release of the NBC and Businessweek interviews, a PR assault worthy of a Steve Jobs product reveal -- an assault that was not without its Jobsian exaggerations. For example, Cook tells NBC's Williams that the glass and the "engine" (i.e. the A6 processor) in the iPhone are made in the U.S. and shipped abroad, leaving the impression that Apple makes those two parts. In fact, Corning (GLW) makes the glass and Samsung, a Korean company, manufactures the processor, albeit to Apple's specs.

Moreover, a U.S.-based Mac manufacturing plant might not create as many jobs as you'd expect. Lenovo announced last month that it was opening up a production line outside Greensboro, NC, and would begin turning out everything from tablets to engineering workstations next year. Total number of new manufacturing jobs for North Carolina residents: 115.

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