U.S. Defense Secretary Leon Panetta has defended plans to gradually wind down military operations in Afghanistan by the end of 2014.

Speaking Sunday on ABC's This Week program, the Pentagon chief said NATO forces still have a fight on their hands, but that “it is on the right track.”

Panetta said there will be no abandonment of a nation that remains at war with radical militants and terrorist elements.

“We are not going anyplace. We have an enduring presence that will be in Afghanistan and will continue to work with them on counter-terrorism. We will continue to provide training, assistance, guidance.”

Critics of a withdrawal timeline say Afghan militants will bide their time until international troops are gone. President Barack Obama's likely Republican opponent in this year's presidential elections, former Massachusetts governor Mitt Romney, said the plans will play into Taliban's hands and could squander hard-fought gains achieved during America's longest-ever war.

“How can you be so misguided and so naive? His secretary of defense said that on a date-certain we are going to pull out our combat troops from Afghanistan. Why in the world do you go to the people you are fighting and tell them the day you are pulling out your troops?”

On another matter, Secretary Panetta criticized Pakistan's imprisonment of a doctor who helped the U.S. catch al-Qaida leader Osama bin Laden. He said it is difficult to understand and it is disturbing that they would sentence this person to 33 years in jail for helping in search for the world's most wanted terrorist. Panetta said “this doctor was not working against Pakistan. He was working against al-Qaida.”

Republican Senator John McCain, told Fox News Sunday that Pakistan's actions in this and other matters are easily understood. He said it is because the Pakistanis and the whole region believe that the U.S. is leaving Afghanistan. He added “they have to live in the neighborhood and are making accommodations, and that is not good for America.”

Defense Secretary Leon Panetta described U.S.-Pakistani relations as “up and down” and one of America's “most complicated.” But he stressed that these ties are important for both sides.