U.S. President Barack Obama and his Republican challenger Mitt Romney intensified attacks against each other on Friday, as they reacted to a newly improved jobs number.

Obama, who was campaigning in Virginia, said at a rally that "today's news is certainly not an excuse to try and talk down the economy to score a few political points. It's a reminder that this country has come too far to turn back now."

He was referring to the Labor Department's announcement that the unemployment rate dropped by 0.3 percentage point to 7.8 percent in September, the lowest level since January 2009 and below the psychological threshold of 8.0 percent.

However, Romney and other Republicans continued their offensive, saying the jobs report was nowhere near good enough.

"There were fewer jobs created this month than last month," Romney said at a rally in Abingdon, Virginia, referring to the revised August figure. "The unemployment rate has come down very, very slowly but it has come down nonetheless. And the reason it has come down this year is that more and more people have just stopped looking for work."

Some conservatives questioned the jobs number, crying conspiracy. Jack Welch, former head of General Electric, tweeted "unbelievable jobs numbers... these Chicago guys will do anything... can't debate so change numbers."

Florida Republican Rep. Allen West wrote on Facebook that "somehow by manipulation of data we are all of a sudden below 8 percent unemployment, a month from the presidential election."

The accusations were dismissed by the White House. Josh Earnest, the White House deputy spokesman, told reporters on Obama's campaign trail that the conspiracy theories were "utter nonsense."

"Anybody -- any serious person who has any familiarity with how these numbers are tabulated understands that these are career employees at the Bureau of Labor Statistics that are responsible for compiling and analyzing these numbers, and they do that on their own," said Earnest.

Jen Psaki, an Obama campaign spokeswoman, told reporters that " we also saw Mitt Romney say that this was the result of people removing themselves from the workforce. That's false. So it shouldn't come as a surprise given this week he's been playing pretty fast and loose with the facts."