WASHINGTON - Pakistan on Thursday dismissed allegations contained in an American newspaper report insinuating ISI’s involvement in the claim that the CIA’s top operative in Islamabad, who was pulled out of the country two months after the killing of Osama bin Laden, was poisoned.

“Obviously the story is fictional, not worthy of comment,” Pakistani Embassy spokesman Nadeem Hotiana said, referring to The Washington Post dispatch. “We reject the insinuations implied in the allegations.”

The Post said that Mark Kelton, the CIA station chief, was moved out of Pakistan in an abrupt move vaguely attributed to health concerns and his strained relationship with Islamabad. “But agency officials continue to think that it is plausible — if not provable — that Kelton’s sudden illness was somehow orchestrated by Pakistan’s Inter-Services Intelligence, known as the ISI,” the Post said in a front-page report.

“The disclosure is a disturbing postscript to the sequence of events surrounding the bin Laden operation five years ago, and adds new intrigue to a counterterrorism partnership that has often been consumed by conspiracy theories,” it said.

That 2011 timeframe, the report pointed out, was marked by extraordinary turbulence in the US relationship with Pakistan, a wary alliance that was close to collapse when US Navy SEALs descended on the Al-Qaeda leader’s compound in Abbottabad.

The Post said Kelton, 59, declined multiple requests for an interview, but that in a brief exchange by phone he said the cause of his illness “was never clarified,” and added that he was not the first to suspect that he had been poisoned.

“The genesis for the thoughts about that didn’t originate with me,” he said.

In the conversation, Kelton declined to answer questions about his illness or tenure in Pakistan. “I’d rather let that whole sad episode lie,” he said.

“I’m very, very proud of the people I worked with who did amazing things for their country at a very difficult time. When the true story is told, the country will be very proud of them.”

US officials, according to the report, acknowledged that the CIA never obtained clear evidence that Kelton was poisoned or confronted Pakistan with that charge. Even so, current and former US intelligence officials claimed that the ISI has been linked to numerous plots against journalists, diplomats and other perceived adversaries, and that the spy agency’s animosity toward Kelton was intense.

Officials said that the ISI chief at the time, Ahmed Shuja Pasha, routinely refused to speak with Kelton or even utter his name.

“Although Kelton’s tenure lasted only seven months, it was in many ways a parade of humiliation for his host,” it said. Within days of Kelton’s arrival, one of his subordinates, CIA contractor Raymond Davis, was involved in a shootout in Lahore.

Kelton signed off on dozens of drone strikes that infuriated the Pakistanis. He also presided over the final preparations for the assault in Abbottabad that killed bin Laden and, to many, exposed Pakistan’s security agencies as incompetent.

According to the Post, the CIA declined to comment.

US officials emphasised that the relationship with Pakistan had been deteriorating for years before Kelton arrived in Islamabad.

By 2009, US officials claimed, US intelligence agencies were convinced that the ISI routinely tipped off its proxies when they were about to be struck by CIA drones.

The strain intensified in 2010 when the CIA sharply escalated the pace of its drone campaign and Pasha was named in a Mumbai attack-related lawsuit in the United States, the Post said.

In apparent retaliation, a suit filed in Pakistan by alleged victims of a drone strike revealed the name of the CIA’s then-station chief, Jonathan Bank.

Concerned for Bank’s safety, the CIA employed a modest ruse to get him out of the country, former officials said. As CIA Deputy Director Michael Morell finished a series of scheduled meetings in Islamabad, Bank escorted his boss to a waiting agency plane. Then, without any notice to Pakistani authorities and in violation of protocol, Bank stayed on board as the flight crew closed the door.

The next station chief would face a doubly daunting assignment — managing the toxic relationship with the ISI while secretly pursuing the most promising lead in more than a decade on bin Laden’s whereabouts.

Kelton, known for an acerbic personality, was not an obvious candidate for the role. He had little experience with counterterrorism operations and had spent much of his career in traditional Cold War outposts, including Moscow, where the CIA remained locked in a decades-long duel with the KGB and its successor organisation.

But given the increasingly tense atmosphere in Islamabad, CIA Director Leon Panetta and others concluded that years of waging adversarial espionage could be an asset. “They thought his Moscow experience was a very good credential,” a former senior CIA official was quoted as stating by the Post.

In a recent interview, former US Ambassador Cameron Munter described 2011 as “by far my most difficult year in the Foreign Service.” Attempts to reach Pasha through the Pakistan Embassy in the US were unsuccessful, the Post said.

On the first night in May, as midnight approached in Pakistan, Kelton, Munter and a senior US military official gathered in a secure CIA room in the Embassy to watch footage from a stealth drone circling over Abbottabad as the bin Laden raid began.

The trio had made secret preparations for possible Pakistani reprisals, officials said, drafting evacuation plans that called for employees at scattered US diplomatic sites to flee across the border into India or be scooped up by the USS Carl Vinson from the Karachi shore. Those at the Embassy would have to hunker down.

At first, it said, Pakistan seemed paralysed by the raid. But amid mounting public anger and recriminations from abroad — Panetta accused Islamabad of being inept or complicit — senior Pakistani officials began to lash out.