PAKISTAN has come under increased international scrutiny after it emerged Osama bin Laden had been hiding in a compound in the country for more than six years before he was found and killed.

Politicians in the US demanded a review of the billions of dollars in aid Washington gives to the nuclear-armed country as questions continued over whether Pakistan’s military and intelligence agencies were too incompetent to catch the al Qaeda leader, knew all along where he was hiding or could even have been complicit.

Prime Minister David Cameron, meanwhile, said authorities in Islamabad had “searching questions” to answer about how bin Laden came to be living in a comfortable mansion in the heart of the garrison city of Abbottabad.

Pakistani President Asif Ali Zardari, issuing his first response to questions about how the world’s most-wanted man was able to live undetected for so long near Islamabad, denied any suggestions that his Government may have sheltered bin Laden.

“The war on terrorism is as much Pakistan’s war as it is America’s,” Mr Zardari wrote in an opinion piece in the Washington Post.

“Some in the US press have suggested that Pakistan lacked vitality in its pursuit of terrorism, or worse yet that we were disingenuous and actually protected the terrorists we claimed to be pursuing. Such baseless speculation may make exciting cable news, but it doesn’t reflect fact.”

While Islamabad hailed the killing of bin Laden as an important milestone in the fight against terrorism, Mr Zardari admitted that his security forces were left out of the US mission and his country’s foreign ministry said it had expressed “deep concerns” that the operation was carried out without it being informed in advance.

In a statement, the Pakistan foreign ministry said: “Neither any base nor facility inside Pakistan was used by the US forces, nor did the Pakistan army provide any operational or logistic assistance to these operations conducted by the US forces.

“This event of unauthorised unilateral action cannot be taken as a rule.”

According to the statement, US helicopters entered Pakistani airspace by making use of “blind spots” in the radar coverage caused by the hilly terrain surrounding Abbottabad.

The foreign ministry said the Pakistani air force scrambled its jets within minutes of being informed of the US operation but there was no engagement with the US forces as they had already left Pakistani airspace.

“The Government of Pakistan further affirms that such an event shall not serve as a future precedent for any state, including the US,” the foreign ministry said, adding that such actions can sometimes constitute a “threat to international peace and security”.

Pakistan is a crucial US ally but Western leaders had long been concerned about Islamist militants from al Qaeda, the Taliban and other groups using safe havens and training camps in Pakistan’s remote and largely lawless north west.

For years, Pakistan had said it did not know bin Laden’s whereabouts, vowing that if Washington had actionable intelligence, its military and security agencies would act.

However, the foreign ministry said yesterday that Pakistan’s Inter Services Intelligence (ISI) spy agency had been sharing information about the targeted compound with the CIA from 2009 until the middle of April.

In a statement, it said: “It is important to highlight that taking advantage of much superior and technological assets, the CIA exploited the intelligence leads given by us to identify and reach Osama bin Laden.”

Mr Zardari wrote: “He was not anywhere we had anticipated he would be, but now he is gone. Although the events were not a joint operation, a decade of co-operation and partnership between the US and Pakistan led up to the elimination of bin Laden as a continuing threat to the civilised world.”

CIA director Leon Panetta reportedly said officials kept Pakistani authorities in the dark out of concern that they might “alert the targets” and jeopardise the special forces assault on Sunday night and into the early hours of Monday.

In Islamabad, there was mostly a sense of embarrassment or indifference that bin Laden had managed to lie low for so long. “The failure of Pakistan to detect the presence of the world’s most-wanted man here is shocking,” the Daily News said in an editorial, reflecting the general tone in the media.

In the US, politicians asked how it was possible for bin Laden to live in a populated area near a military training academy without anyone in authority knowing about it and the growing concern led to renewed calls for a review of aid to the country.

Senate Intelligence Committee chairwoman Dianne Feinstein said: “Our Government is in fiscal distress. To make contributions to a country that isn’t going to be fully supportive is a problem for many.”

The US Congress has approved $20 billion (£12.14bn) for Pakistan in direct aid and military reimbursements partly to help Islamabad fight militancy since al Qaeda’s strikes on the US.

The White House acknowledged there was good reason for politicians, already doubtful of Pakistan’s co-operation against al Qaeda, to demand to know whether bin Laden had been “hiding in plain sight” and to raise questions about US aid.

White House counter-terrorism expert John Brennan said it was “inconceivable” that he did not have a support system in Pakistan, a comment backed up by Mr Cameron, who said bin Laden “must have had a support network in Pakistan”.

But Mr Cameron insisted that it was not in Britain’s interests to start a “flaming great row” with Pakistan, which has itself suffered enormously at the hands of militant Islam and shares with the UK in the struggle against terrorism.