The US-led force in Afghanistan has incorrectly reported a decline in Taliban attacks in the country, officials said Tuesday, casting doubts on NATO's claims of progress in the war.
Officials said a reported seven percent decrease in "enemy-initiated attacks" for the whole of 2012 was wrong and insurgent attacks were roughly the same as the previous year.
The incorrect figure had been posted on the website of NATO's International Security Assistance Force (ISAF).
The US government and its allies have repeatedly touted a purported drop in insurgent attacks as proof that the Taliban is on the retreat. But the error in the key statistic raised questions about how governments and commanders are portraying the war effort.
Officials said the mistake occurred because some Afghan units have only recently taken the lead from NATO-led forces in some areas and had not entered numbers correctly into a database.
"The error is down to a large number of Afghan units coming online, a fact of their taking the lead in 2012 for the first time in a majority of districts," said a US defense official, who spoke on condition of anonymity.
The accurate number for insurgent attacks in 2012 showed the assaults had remained at the same level as in 2011, the official said.
"Overall, the numbers are about the same," the official said.
Defense Secretary Leon Panetta, top military leaders and other senior officials often refer to promising security trends in Afghanistan and that violence and attacks are down from previous periods.
In a report to Congress issued in October, the Pentagon hailed what it called a drop in enemy attacks, with the decline registering in May and running through September 2012.
The admission of the clerical error on Tuesday raised questions about the accuracy of the statistics cited by the Pentagon and NATO, particularly as the latest numbers are being compiled by Afghan troops and police with modest training and low literacy levels.
The US defense official said the "enemy-initiated attacks" statistic is "the best measure we have but it's not perfect."
The official insisted that the war effort was on track and that the error did not change the Pentagon's assessment of the campaign.
"We remain confident that we're seeing progress," with the insurgency forced to operate away from populated areas, the official said.