Updated

A Pakistani militant group has denied any links with the doctor who helped the U.S. track down Osama bin Laden, threatening Thursday to kill him for working with the Americans.

The statement by Lashkar-e-Islam was the latest twist in the case of Shakil Afridi, whose plight has angered Washington and opened up another crack in relations with Islamabad.

Afridi ran a vaccination campaign on behalf of the CIA as a way of collecting blood samples from bin Laden's family in their house in northwest Pakistan. Afridi was arrested soon after the May 2 American raid that killed the al-Qaida leader. Last week he was sentenced to 33 years in prison, angering many in the United States.

It was initially assumed Afridi had been convicted of crimes relating to his work with the CIA, but on Wednesday the court released its written verdict, which found Afridi guilty of assisting Lashkar-e-Islam, a brutal militant and criminal gang operating in Khyber tribal region, where Afridi worked.

In a brief interview, Lashkar commander Abdul Rasheed denied that Afridi was a supporter, adding, "we will kill the foreign agent, if we get an opportunity."

Rasheed said that the group once took Afridi captive because locals said he was taking money from them, but set him free after a warning. A relative said last week that Lashkar kidnapped him, and he had to pay a large ransom for his release. At a news conference this week, Afridi's brother and lawyers said he had done nothing wrong.

Afridi's case is sensitive for Pakistan's powerful spy agencies, and many people assume they are controlling the narrative surrounding him. Pakistan was deeply embarrassed by the U.S. raid that killed bin Laden, carried out without informing Pakistani authorities in advance.

Pakistan has blocked NATO and U.S. supply lines to the Afghan war fronts since November. The United States wants them to reopen, but talks are apparently deadlocked over the price that Washington is prepared to pay Pakistan for the use of its territory for transit.