WASHINGTON - A Republican senator is holding up President Barack Obama’s nominee for ambassador to Pakistan to send Islamabad a message about the arrest of a Pakistani doctor who helped the CIA track down Osama bin Laden, The Hill, a Congressional newspaper, reported Saturday.

Senator Rand Paul objected to the nomination of Ambassador Richard Olson, who is now serving at the US embassy in Afghanistan, pushing off his confirmation by the Senate until at least September.

A staunch defender in Congress of Dr Afridi, Senator Paul has doggedly pursued a vote on a bill that would strip all US aid to Pakistan unless the doctor is released from prison.

The Hill said some Congressional leaders warn that the hold on Olson’s nomination could backfire by further damaging America’s strained relations in a strategically vital part of the world. “Democrats and Republicans always say that the key to Afghanistan is securing cooperation with Pakistan,” Senate Foreign Relations Committee Chairman John Kerry, a Democrat, told The Hill, when asked about the hold. “That’s reason enough to have a top notch diplomat in place in Islamabad. This is a complicated relationship that demands constant attention.”

Paul’s office did not respond to a request for comment, The Hill said.

Two senior Senate aides told The Cable, a subsidiary of Foreign Policy magazine, that the nominations of both Olson and James Cunningham to be the next ambassador to Pakistan and Afghanistan, respectively, were at risk of not being included in the string of nominations confirmed by the Senate by unanimous consent late Thursday, just before senators adjourned for a five-week recess. The outgoing US ambassador to Afghanistan, Ryan Crocker, whose health is declining, intervened and made calls on behalf of Cunningham and Olson, but only Cunningham got confirmed.

“The concerns about Olson, who previously served as ambassador to the United Arab Emirates, aren’t personal, but committee members want more detail on the would-be envoy’s proposed approach to the Haqqani network, the militant group that has been waging cross-border attacks on US forces in Afghanistan,” The Cable said. Olson promised to make the issue a priority at his July 31 confirmation hearing, but multiple senators want to use the opportunity to gauge if the administration plans to include the Haqqani network in any effort to negotiate an end to the Afghanistan war.

A defiant Paul told The Cable that he will keep pressing the issue unless Afridi is released.

“Senate leadership is dead-set against letting Paul have a vote on his amendment, out of concern that senators won’t want to publicly stand up in defence of sending more American taxpayer money to Pakistan,” The Cable said. But Paul said he plans to use Senate Rule 14 to force a vote. It’s not clear if this legislative tactic will work, but Paul is confident.

“We are still hopeful that Pakistan will relook at the evidence and decide that they don’t want to hold him. If they do, we will probably not press for the vote. If they don’t, I have 16 signatures to try to force a vote,” Paul said. “It’s not a guarantee I’ll get a vote, but it’s a guarantee I’ll be a thorn in somebody’s side.”

Meanwhile, Olson is headed to Islamabad, where he has already started work as the charge d’affaires, but he will not be leading the embassy with the ambassador title and the gravitas that goes with it. “It’s doubtful that the Pakistanis will free Afridi to satisfy Paul, and senior senators lament the delay in Olson’s confirmation,” The Cable said.