Al-Qaeda leader Bin Laden 'dead'. Again.

[Peter Lemkin]

US-Pakistan relations have hit a new crisis with the outing of the US's top spy in Islamabad.

Mark Carlton, the purported CIA station chief, was named by a Pakistani newspaper and a private television news network over the weekend, the second holder of that post in less than a year to have his cover blown by the media, presumably with official consent.

The first report by ARY, a private Pakistani television channel, documented a meeting between Mr Carlton and the head of the Inter-Services Intelligence spy agency, suggesting that the information came from them.

The CIA and the ISI have refused to comment.

Some US officials suspected the move was ISI retaliation for the naming of its chief, Lieutenant General Ahmad Shuja Pasha, in a US lawsuit relating to the Mumbai terrorist attacks. Since then, Pakistan and the CIA have tussled over a CIA contractor's shooting of two armed Pakistanis under disputed circumstances.

The Islamabad station chief is one of the CIA's most critical and sensitive assignments. The position oversees the agency's covert programs, including the drone campaign that targets al-Qa'ida and Taliban leaders, as well as fighters who cross the border into Afghanistan.

The purported name of the CIA's station chief was first reported on Friday by ARY. The station was reporting on a meeting between the director of Pakistan's spy service, the Directorate of Inter-Services Intelligence and the station chief.

"If we did not mention the man's name, the credibility of the story would have been reduced," said ARY's Islamabad bureau chief, Sabir Shakir.

Shakir wouldn't discuss who had provided the name, but said he had "one-plus" sources.

The story was picked up by the Nation, a right-wing newspaper that has often accused American diplomats and private citizens in Pakistan of working for the CIA. The Nation's editor, Salim Bokhari, said he didn't know how the name became public.

"It has to have been released by some government agency," Bokhari said. "Who else would know such information?"

A former senior US intelligence official said any outing of agents would be Pakistan's "own little way of retaliating," given how "very, very upset and embarrassed" the government remains over the raid in Abbottabad and its aftermath. Pakistan has long been uncomfortable with the extent of CIA operations inside the country even before the bin Laden raid and revelations about a secret CIA station in Abbottabad.

Raymond Davis, a CIA agent, spent months in jail in Lahore after shooting two men, believed to be ISI officers tailing him, before Washington could secure his release. Mr Carlton's predecessor had to flee Pakistan last year after his identity was exposed in the Pakistani press. If the revelation about his identity is correct, Mr Carlton will have almost certainly already left the country, dealing a further blow to US intelligence operations there.