Making progress in Afghanistan is both "harder" and going more slowly than anticipated, Leon Panetta, director of the Central Intelligence Agency (CIA), said on Sunday.

While recognizing the U.S. military has made progress in Afghanistan in terms of its counterinsurgency efforts, Panetta said that it's slower than anyone anticipated and becomes harder considering the "serious problems" surrounding the war-torn country.

"We're dealing with tribal societies. We're dealing with a country that has problems with governance, problems with corruption, problems with narcotics trafficking, problems with a Taliban insurgency," he told the ABC network's "This Week" program.

"The key to success or failure is whether the Afghans accept responsibility, are able to deploy an effective army and police force to maintain stability," he said. "If they can do that, then I think we're going to be able achieve the kind of progress and the kind of stability that the President is after."

Panetta's comments comes at a time when President Barack Obama's new Afghan strategy is suffering significant setbacks. The strategy, which was unveiled in December, called for a buildup of 30,000 troops in Afghanistan, with a total of 98,000 by fall.

Military operations by U.S. and NATO forces in Afghanistan did not go as smoothly as previously expected. Militants have regained momentum in Marja, southern Afghanistan, where U.S. and NATO forces mounted a major push against Taliban earlier this year. As a result, military operations to secure Kandahar, the birthplace of Taliban in Afghanistan, have been pushed back.