NATO''s top official took issue on Sunday with Afghanistan''s sluggish forward progress, placing blame more on the country''s weak leadership than on the Taliban-led insurgency.

"Afghan leadership is not some distant aspiration -- it''s something that we need as soon as possible and on which we must insist," NATO Secretary-General Jaap de Hoop Scheffer wrote in an opinion piece published in Sunday''s Washington Post.

Seven years ago the United States sent troops to Afghanistan in response to the September 11, 2001, attacks by al Qaeda, toppling the leading Taliban group that had been sheltering al Qaeda''s leaders.

President-elect Barack Obama has committed to sending more U.S. forces to Afghanistan to tackle insurgent violence that has risen in recent years.

De Hoop Scheffer said the basic problem in Afghanistan is not too much Taliban but the country has too little central control. The longer it takes to see progress, he said, the longer the military operation remains in place at a "real cost in lives."

"But we have paid enough, in blood and treasure, to demand that the Afghan government take more concrete and vigorous action to root out corruption and increase efficiency, even where that means difficult political choices," Scheffer said.

The United States currently has about 33,000 troops in Afghanistan and plans to add at least another 13,000 forces by summer, according to Pentagon officials.

De Hoop Scheffer wrote that while NATO is obliged to keep ramping up the military operation, force alone cannot solve Afghanistan''s problems.