The United States Wednesday refrained from denouncing the 33-year jail sentence of a Pakistani physician who helped it to find the late al-Qaeda leader Osama bin Laden, saying there were other "options", dpa reported.
The court's judgement meanwhile drew an angry response from two US senators, who said it would raise questions about future US funding to Pakistan.
Shakeel Afridi was sentenced under treason laws by a Pakistani court, according to Pakistani official earlier Wednesday. He was accused of carrying out a fake vaccination campaign on behalf of the CIA that helped the US intelligence agency track bin Laden in Abbottabad, just 60 kilometres from Islamabad.
US State Department spokeswoman Victoria Nuland said the US position had not changed since February, and did not acknowledge that Afridi had been convicted of treason.
"We continue to see no basis for ... Dr Afridi to be held," she said. "It's not clear that the legal process is over ... There may be other options for him legally."
The conviction and sentencing for treason was condemned as "shocking and outrageous" by US Senators John McCain and Carl Levin, who called for the Pakistani government to pardon and release Afridi "immediately."
"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," they said in a joint statement.
They said Afridi had acted in conformity with multiple UN Security Council resolutions which required the international community to help bring bin Laden and the al-Qaeda terrorist network to jutice.
"Dr Afridi set an example that we wish others in Pakistan had followed long ago. He should be praised and rewarded for his actions, not punished and slandered," the senators said.
Imprisonment of Afridi will do "further harm" to US-Pakistani relations and would diminish congressional willingness to provide financial aid to Pakistan, they said.
The sentence is likely to further complicate negotiations between the two sides on reopening NATO supply routes to international forces in Afghanistan.
Pakistan last year closed supply routes to NATO-led forces in Afghanistan after a US airstrike on Pakistani army border posts killed 24 soldiers.