Washington- Describing the reduction in the jail term of Shakeel Afridi as a positive step, the US on Tuesday reiterated its demand for release of the Pakistani doctor who helped the CIA trace al Qaeda leader Osama bin Laden."We've seen the reports that Dr Afridi's sentence was reduced from 33 to 23 years. While the reduction in the sentence is a positive step, our concerns about Dr Afridi's arrest and conviction remain unchanged," State Department spokesperson Jen Psaki said at her daily news conference.A Pakistani tribunal last week upheld the conviction of Afridi but reduced his 33-year sentence by 10 years. "As 23 years is just as unjust and unwarranted as 33 years, we are continuing unabated the efforts we've had underway since Dr Afridi was first arrested," Psaki said. "Which is to state unequivocally and consistently to the Pakistani government that the prosecution and conviction of Dr Afridi sends exactly the wrong message about the importance of our shared interests in counterterrorism and in particular bringing Osama bin Laden to justice," she said.The doctor, who was arrested immediately after the May 2, 2011 operation by US commandos that killed bin Laden, was convicted for treason over alleged ties to banned militant group Lashkar-e-Islam. Bin Laden was killed in the unilateral US commando raid in Abbottabad, sending bilateral relations into a tailspin and embarrassing Pakistan's powerful military. Afridi is currently held at the Peshawar central prison. It is said that Afridi ran a fake vaccination camp to gain access to bin Laden's family but legal experts and rights activists have challenged his sentence.