The Obama administration appears to have relied on misleading figures to characterize progress in the war in Afghanistan, as the U.S.-led military coalition acknowledged Tuesday that it had incorrectly reported a decline in Taliban attacks last year.
Throughout the campaign season, President Obama and his top officials claimed the Taliban were on the decline.
"We broke the Taliban's momentum," Obama said from Bagram Air Base last May.
"We've blunted the Taliban's momentum," he said last September, as he accepted the party's nomination.
But the corrected numbers could undercut that narrative.
The U.S.-led coalition had incorrectly reported a 7 percent decline in Taliban attacks last year. In fact, there was no change in the number of attacks on international troops from 2011 to 2012.
"It certainly runs against the administration narrative that things are getting better in Afghanistan," said Peter Brookes, a senior fellow with The Heritage Foundation.
A spokesman for the U.S.-led coalition said the mistakes were noticed "during a quality control check."
Officials attributed the miscounting to clerical errors and said the problem does not change officials' basic assessment of the war.
"The percentage of attacks in 2012 compared to 2011 was about flat," one official said. "But again, our assessment of the fundamentals of campaign progress has not changed. The enemy is increasingly separated from the population and the (Afghan forces) are currently in the lead for the vast majority of partnered operations."
U.S. and allied officials have often cited declining violence as a sign that the Taliban has been degraded and that Afghan forces are in position to take the lead security role when the last U.S. combat troops leave Dec. 31, 2014.
In mid-December, Defense Secretary Leon Panetta said "violence is down," in 2012, and that Afghan forces "have gotten much better at providing security" in areas where they have taken the lead role. He said the Taliban can be expected to continue to attack, "but overall they are losing."
On Tuesday, Pentagon spokesman George Little said Panetta was "concerned to learn of the errors" and was only very recently briefed on the matter.
"This particular set of metrics doesn't tell the full story of progress against the Taliban, of course, but it's unhelpful to have inaccurate information in our systems," Little said.
The Taliban have lost a good deal of territory since a 2010 surge of U.S. forces in the southern provinces of Helmand and Kandahar, and they failed to recover it during the last two fighting seasons. Even so, they are resilient, and they are expected to severely test Afghan forces as the U.S. and its coalition partners step further into the background this year and complete their combat mission next year.
A coalition spokesman, Jamie Graybeal, did not fully explain ISAF's erroneous reporting of 2012 Taliban attacks. It was not clear, for example, at what point the data errors began or who discovered them.
Graybeal said an audit determined that portions of the data from unilateral Afghan military operations were "not properly reflected" in the trends ISAF had reported in its monthly updates.
"After including this unilateral ANSF (Afghan National Security Force) data into our database, we have determined that there was no change in the total number of EIAs (enemy initiated attacks) from 2011 to 2012," Graybeal said.
"This was a record-keeping error that we recognized and have now corrected," he added.
The coalition defines enemy initiated attacks as attacks by small arms, mortars, rockets and improvised explosive devices, or IEDs. But it does not include IEDs that are found and cleared before they explode.
Trends in Taliban attacks are one yardstick used by ISAF to measure war progress. Others include the state of security in populated areas, the number of coalition and Afghan casualties, the degree to which civilians can move about freely, and the performance of Afghan security forces.
Fox News' Jennifer Griffin and Justin Fishel and The Associated Press contributed to this report.