Defense Secretary Leon Panetta said Sunday that the United States is not about to "get gouged" by Pakistan -- which despite having received billions in U.S. aid is demanding $5,000 for every truck that carries supplies into Afghanistan across its border. 

The dispute over the border crossing is once again in the spotlight after Pakistan sentenced to 33 years in prison the Pakistani doctor who helped the CIA track down Usama bin Laden. 

Panetta on Sunday called that decision "disturbing," though he said the U.S. government will continue to "work at" its troubled relationship with Pakistan. Yet with Islamabad continuing to try and extract money from the U.S. over the still-closed border crossing, Panetta insisted Sunday that the United States will only pay a "fair price" for that access. 

"We're not about to get gouged in the price. We want a fair price," Panetta said on ABC's "This Week." 

Pakistan closed supply routes for NATO forces after a friendly-fire incident in which U.S. forces unintentionally killed two-dozen Pakistani soldiers last November. 

The U.S. used to pay $250 for every truck that crossed before the attack. Now with the crossings still closed, Pakistan wants $5,000. 

The demand has angered U.S. officials, and it was only compounded by the prison sentence handed down this past week for Dr. Shakil Afridi. 

Panetta stressed Sunday that he wants Pakistan to understand Afridi was working toward a common goal. 

"This doctor was not working against Pakistan. He was working against Al Qaeda," Panetta said. "And I hope that ultimately Pakistan understands that." 

Administration officials have condemned Pakistan's decision, as have a number of U.S. lawmakers -- who this past week voted on a Senate panel to cut Pakistan's aid by $33 million, or $1 million for every year of Afridi's sentence. 

Some lawmakers and ex-intelligence officials have said the administration could have done a better job providing for Afridi's security, with the understanding that his work would leave him vulnerable to Pakistani retribution. 

Panetta, speaking on ABC's "This Week," did not discuss that criticism but made clear he shares their outrage toward Islamabad. 

"It is so difficult to understand, and it's so disturbing that they would sentence this doctor to 33 years for helping in the search for the most notorious terrorist in our time," he said. 

Panetta, citing Pakistan's nuclear weapons arsenal and "critical" place in the region, said the U.S. and Pakistan would continue to try and work together. 

"What they have done here does not help in the effort to reestablish a relationship between the United States and Pakistan," he said. 

He added: "We have to continue to work at it. ... They're dealing with the terrorist threat just like we are, so our responsibility here is to keep pushing them to understand how important it is for them to work with us to try to deal with the common threats we both face -- and what they did with this doctor doesn't help in the effort to try to do that." Â