Afridi has been slapped with new murder charges and is already serving a 30-year sentence.
"We are concerned about the new charge brought late last week against Dr Afridi, the Pakistani doctor, who aided in the intelligence-gathering effort that made possible the killing of the world's most wanted terrorist, Osama bin Laden," State Department spokesperson Jen Psaki said yesterday.
"His assistance in confirming the location of bin Laden was a service to the entire world and to Pakistanis who had lost loved ones and suffered at the hands of Al Qaida. We've called on proper authorities to ensure that Dr Afridi receives a fair trial for this new charge," she said.
The issue was raised at the highest level by US President Barack Obama when he met Pakistani Prime Minister Nawaz Sharif at White House last month but there was no assurance from the latter.
"We regret that he was convicted and at the severity of his sentence. We've expressed that in the past before, as well. And we've conveyed that very clearly to the Pakistani government," Psaki said.