Updated

A Republican congressman called Thursday for a "massive outpouring" of pressure to compel Pakistan to release from prison the doctor who helped find Usama bin Laden, warning that the U.S. would be setting an "immoral and cowardly" example by failing to secure his release.

"It's a horrible message to send," Rep. Dana Rohrabacher, R-Calif., told FoxNews.com.

Dr. Shakil Afridi was sentenced Wednesday to 33 years in prison for his role aiding the CIA by running a vaccine program to try and collect bin Laden's DNA.

Rohrabacher, who has unsuccessfully pushed resolutions to award Afridi the Congressional Gold Medal and grant him U.S. citizenship, cast the U.S. response to that sentencing as a critical moment for America.

"I think that there needs to be a massive outpouring on the part of the American people and the part of their elected representatives to prove to the government of Pakistan that it is making huge enemies for itself by being vindictive against this man. For what? For helping us bring to justice the mass murderer of Americans," he said.

Rohrabacher continued: "Heroes are heroic people because they risk great suffering. But how we deal with this heroic person ... what we do now will be defining ourselves, our own character."

He said that not only would it be "immoral and cowardly" to abandon him, but it would also deter others from working with the U.S. in the future.

The Obama administration claims it's been pressing Afridi's case with Islamabad all along.

"We have regularly taken up this matter with Pakistan. I would expect we will continue to," State Department spokeswoman Victoria Nuland said.

Rohrabacher said he assumed there was "quiet diplomacy going on" in the aftermath of Afridi's arrest. But he questioned whether the case fell through the cracks.

"Unfortunately, there are so many things on the plate for these guys to be doing quiet diplomacy about (with Pakistan) that the plate's a little overloaded, that it might just have fallen on the ground and broken," he said.

He added: "The administration hasn't done anything to indicate they are serious about the demand for this man's release."

Going forward, he urged Washington to get serious about cutting off Pakistani aid.

"(Pakistan has) disclosed to the American people the fundamental anti-American nature of their regime in this mean-spirited, vile persecution of a man who was trying to help us bring justice to the mass murder of 3,000 American citizens," he said.