Welch did not respond to a request for further comment. In an interview later in the day on MSNBC, he admitted that he had no evidence that the jobs numbers were manipulated, but said they "defy logic."
The unemployment rate fell to 7.8% in September, down from 8.1% a month earlier. The drop was due to the Bureau of Labor Statistics' survey of households showing that 873,000 more people had jobs than in the previous month. That was the biggest one-month gain in more than nine years.
Labor Secretary Hilda Solis criticized the conspiracy theories Friday.
"This is a methodology that's been used for decades. And it is insulting when you hear people just cavalierly say that somehow we're manipulating numbers," Solis told CNN's Richard Quest.
Welch wasn't alone in raising questions about the jobs numbers.
Americans for Limited Government, a conservative group that has been a steady critic of the Obama administration, issued a statement that said the numbers the BLS "used to calculate the unemployment rate are wrong, or worse manipulated. Given that these numbers conveniently meet Obama's campaign promises one month before the election, the conclusions are obvious. Anyone who takes this unemployment report serious is either naive or a paid Obama campaign adviser."
Conn Carroll, a senior writer at the conservative Washington Examiner suggested a slightly less nefarious form of manipulation of the data.
"I don't think BLS cooked numbers. I think a bunch of Dems lied about getting jobs. That would have same effect," he tweeted. "Would love to see the partisan breakdown of the 873,000 Americans who say they got new jobs."
BLS denied there was any manipulation of the data or anything out of the ordinary about the unemployment rate calculation.
"No political appointee is involved in the collecting, processing and analyzing of the data," said Thomas Nardone, the associate commissioner for employment and unemployment statistics.
Nardone said the Council of Economic Advisers doesn't get the numbers until Thursday afternoon, and that the Secretary of Labor he rself doesn't see them until Friday morning.
Even some conservative economists defended the BLS's integrity and legitimacy of the numbers.
"The jobs #'s may look fishy to some, but if you step back, it's just a plow horse economy lumbering along," tweeted Brian Wesbury, chief economist at First Trust.
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