NEW YORK — Jack Welch, writing on his Twitter account, said Friday that the Obama administration manipulated US employment data for political gain by showing a drop in the jobless rate.
‘‘Unbelievable jobs numbers..these Chicago guys will do anything..can’t debate so change numbers,’’ the former General Electric chief executive officer said in a message posted immediately after the Labor Department reported that the unemployment rate fell to 7.8 percent last month, the lowest since President Barack Obama took office in January 2009.
The Obama administration denied the allegation as baseless and defended the Bureau of Labor Statistics, which computes the figures. Alan Krueger, chairman of the White House Council of Economic Advisers, told Bloomberg Television that Welch’s remark was ‘‘irresponsible.’’
The message from Welch, 76, a supporter of Republican nominee Mitt Romney, went viral on the social-media site as political commentators and individuals weighed in. Welch took aim at the figures that may matter most before Election Day on Nov. 6, because the October report due on Nov. 2 may be too late to change voters’ perceptions about the economy.
Welch’s own profile assured that his message would attract attention, and Twitter users had resent the comment 2,361 times as of noon in New York. His success as GE’s CEO for 20 years through 2001 and as a business-book author has made him one of the nation’s most-recognized retired executives.
‘‘His words ring louder than many others and that’s just the fact of life for a CEO, especially a well-known corporate icon type CEO that he has been,’’ said Peter Thies, a senior partner at Los Angeles-based executive search firm Korn/Ferry International.
Jen Psaki, an Obama campaign spokeswoman, declined to comment, as did Gary Sheffer, vice president of communications and public affairs at GE. The Romney campaign had no immediate comment.
Welch was in meetings Friday and unavailable for comment, said Rosanne Badowski, his executive assistant. She said Welch is the only one with access to the Twitter account.
‘‘No serious person would question the integrity of the Bureau of Labor Statistics,’’ Krueger said in the Bloomberg Television interview. ‘‘These numbers are put together by career employees. They use the same process every month. So I think comments like that are irresponsible.’’
Labor Secretary Hilda Solis, whose department produces the employment figures, called Welch’s remarks ‘‘really ludicrous’’ in an interview on CNBC.
Welch, who has a home in North Palm Beach, Fla., has contributed $5,000 to Romney’s campaign, the maximum amount anyone can donate to a presidential candidate, according to the Center for Responsive Politics, a Washington-based research group that tracks political giving.
‘‘In my lifetime, Mitt Romney is the most qualified leader I’ve ever seen run for the presidency of the United States,’’ Welch told CNBC in a January interview.
Welch posted a Twitter message Thursday night broaching the idea that the jobless rate would come in at less than 8 percent, after staying at that level or higher since February 2009, the longest stretch since monthly jobless figures were first compiled in 1948.
‘‘At 7.9 it would be Chicago and labor Sec in action,’’ Welch wrote.
That Chicago reference and the one today alluded to the city where Obama got his start in electoral politics and where his re-election campaign is based. Many of Obama’s political opponents over the years have criticized him for association with so-called Chicago style politics and its reputation for corruption.
Douglas Holtz-Eakin, who was chief economist on President George W. Bush’s Council of Economic Advisers in 2001-2002, said it wasn’t uncommon to have numerical surprises in the monthly Labor Department data.
‘‘I’ve never been one of those who felt that the numbers get doctored,’’ he said in a Bloomberg Television interview. ‘‘These are professionals. They do this as a career. I have a lot of respect for them. But like any other enterprise, every now and then you just get a weird number, and this one makes no sense.’’
Friday’s report gave Obama a new chance to talk about how the economy is improving. The drop to under 8 percent is ‘‘symbolically important’’ to voters, said Alan Abramowitz, a political scientist at Emory University in Atlanta.
Forecasters had expected the rate to rise to 8.2 percent from 8.1 percent in August, according to the median prediction of economists surveyed by Bloomberg News. The jobless rate had fluctuated between 8.1 percent and 8.3 percent since the beginning of the year.
As CEO, Welch earned the nickname ‘‘Neutron Jack’’ after cutting more than 100,000 jobs in the 1980s to help boost profits.
His successor, Jeffrey Immelt, was chosen by the White House in January 2011 to lead a panel of CEOs, labor leaders and academics charged with recommending ways to boost US employment. The President’s Council on Jobs and Competitiveness delivered its report to Obama in January.
_With assistance from Michael Tackett, Mike Dorning, Jonathan D. Salant, Hans Nichols and Steven Komarow in Washington, Thomas Black in Dallas, Rachel Layne in Boston and Edmund Lee in New York.