WASHINGTON - The US Central Intelligence Agency (CIA) failed to conduct an operation to stage a prison break for Pakistani doctor Shakil Afridi who had helped US authorities track down al-Qaeda founder Osama bin Laden, a Russian news agency has claimed citing a source familiar with the situation.

The report, quoting another source, states that Washington had earlier requested Islamabad to extradite Afridi to the US.

The source went on to suggest that Afridi's release and extradition is crucial for other CIA operations in Asia.

After his detention in 2011, Afridi was sentenced to 33 years for involvement in anti-State activities by a tribal court in 2012.

However, the sentence was later reduced.

Afridi was recently shifted, as per media reports, from Peshawar to Adiala Jail in Rawalpindi due to security concerns.

However, a source familiar with the situation told Sputnik that the doctor was placed in another jail because of the planned prison break.

His brother and lawyer have claimed the move precedes his release from prison as he has served the minimum sentence.

The CIA, in turn, refused to comment on news that Pakistani intelligence thwarted the agency's plan to orchestrate a prison escape for Afridi.

Also on Monday, a US Department of State official told Sputnik that Washington hopes that the Pakistani authorities will take all necessary measures to ensure the safety of Shakeel Afridi.

"Pakistan has assured us that Dr Afridi is being treated humanely and is in good health," the official stressed.

The issue of Afridi's release is reportedly one of the major obstacles to the improvement of ties between the US and Pakistan.

Soon after the death of Osama bin Laden in May 2011 in a US raid in Abbottabad, the US media reported that Afridi had contributed to the success of the CIA operation by collecting DNA samples of bin Laden's family by order of the intelligence agency.

Then-CIA Director Leon Panetta and the then US Secretary of State Hillary Clinton had confirmed the doctor's role in eliminating the terrorist, after which Afridi was arrested by the Pakistani authorities.