PESHAWAR, Pakistan (AFP) ― A Pakistani surgeon recruited by the CIA to help find Osama bin Laden was Wednesday sentenced to 33 years in prison for treason, sparking a warning from U.S. senators over American aid.

Shakeel Afridi, who was sacked as a government doctor two months ago, was found guilty under the tribal justice system of Khyber district, part of Pakistan’s semi-autonomous tribal belt.

In addition to his jail sentence, he was fined 320,000 rupees ($3,500). The doctor had worked for years as a surgeon in lawless Khyber, part of the Taliban and al-Qaida infested tribal belt.

Afridi was not present in the court and was not given a chance to defend himself, officials said. Under the tribal system, he would not have had access to a lawyer.

“He has been sentenced for 33 years on treason charges and has been moved to Peshawar central jail after the verdict was announced by the local court,”

said Mohammad Siddiq, spokesman for the administrative head of Khyber.

The stiff punishment came as Washington and Islamabad, allies in the war on terror, struggle to repair ties that hit a low when U.S. forces mounted a secret raid into Pakistan that killed bin Laden in May last year.

They were strained to breaking point in November when U.S. forces staged a botched raid that killed 24 Pakistani troops, prompting Islamabad to cut off the land route for supplies to NATO troops in neighboring Afghanistan.

The U.S. State Department said Wednesday that Pakistan had no basis to hold or charge Afridi.

“We will continue to make those representations to the government of Pakistan,” spokeswoman Victoria Nuland said.

Pentagon press secretary George Little told reporters: “Anyone who supported the United States in finding Osama bin Laden was not working against Pakistan, they were working against al-Qaida.”

And Carl Levin and John McCain, the top senators from the two major U.S. parties on the Senate Armed Services Committee, in a joint statement demanded Afridi be pardoned and freed “immediately,” saying the decision could put U.S. financial assistance at risk.

“What Dr. Afridi did is the furthest thing from treason. It was a courageous, heroic and patriotic act which helped to locate the most wanted terrorist in the world ― a mass murderer who had the blood of many innocent Pakistanis on his hands,” the two senators said.

The United States has provided Pakistan with more than $18 billion in assistance since the Sept. 11, 2001 attacks, but U.S. officials have persistently worried that some elements of the Pakistani establishment have maintained support for extremists.

In January, Defense Secretary Leon Panetta confirmed Afridi had worked for U.S. intelligence by collecting DNA to verify bin Laden’s presence and expressed concern about Pakistan’s treatment of him.

The surgeon was arrested shortly after U.S. troops killed the al-Qaida leader on May 2, 2011 and in October a Pakistani commission recommended that he be tried for treason.

Panetta said he believed someone in authority in Pakistan knew where bin Laden was hiding and as a result Islamabad was not warned about the raid.

Pakistan reacted furiously to what it called a violation of its sovereignty. It insisted it knew nothing about bin Laden’s whereabouts and the operation severely damaged relations with the United States.

Under Pakistan’s tribal justice system, Afridi has the right to appeal.

Critics said Wednesday that he should not have been tried under tribal law in the tribal belt for an alleged crime that took place outside their jurisdiction.

British newspaper The Guardian reported last July that Afridi set up a fake vaccination program in the hope of obtaining DNA samples from those living in the house where the CIA suspected bin Laden was resident to see if they were his relatives.

The United States was not 100 percent sure that the al-Qaida chief was living in the Abbottabad house when President Barack Obama gave the approval for Navy SEALs to raid the compound.