Pakistan's fight against the Taliban has a limited chance of success because of the army's inexperience and its refusal to accept help from the west, according to a counter-insurgency expert.

As Pakistan continued its offensive against the Taliban in the Swat valley to the north-west of Islamabad, David Kilcullen, widely hailed as a key strategist behind the successful US surge in Iraq, warned that the outlook for the operation was "pretty bleak." Mr Kilcullen has been a leading adviser to General David Petraeus, the head of US Central Command, in his Iraq strategy.

The Obama administration has given strong backing to the Pakistani operation in Swat, knowing that success is key to the government's stability. But in an interview with the Financial Times, Mr Kilcullen said he doubted Pakistan could succeed - and that failure would endanger the international mission in Afghanistan because it could cut Nato supply routes.

"The Pakistani military has really no capability for what we would call counter- insurgency," he said. "What they are doing in the Swat valley is a conventional offensive against the main- force Taliban . . . They need a more sophisticated approach and they need training and assistance, which they are currently refusing." Mr Kilcullen said of the Pakistani military: "They will move into Swat, they will fight the Taliban, there will be half a million refugees, there will be immense dislocation. I'm not sure that, looking back on this in six months, we will see any improvement."

He added that Pakistan "has a long history of doing the minimum necessary" to keep western aid flowing into the country. "I hope we will see something different out of this offensive but I remain to be convinced."

Mr Kilcullen said the situation in Pakistan was central to prospects for the Nato mission in Afghanistan. "All the resources we are putting into Afghanistan have to go through Pakistan, with the exception of a small amount that has to fly through Manas airbase," he said. But he warned that Nato might lose its supply routes. "We could be creating a Stalingrad in the Hindu Kush, if we are not careful."

The strategist also warned that US drone strikes in the Pakistani tribal areas aimed at hitting al-Qaeda and Taliban figures were counter-productive. "They have an undeniable benefit, because we have disrupted AQ operations and damaged AQ cells in Pakistan. But they have a negative strategic effect in that they incite Punjabi militancy, which is the biggest problem in Pakistani right now." Mr Kilcullen said the hit rate on drone attacks was "unacceptably low".

He said the US had killed 14 mid-level or lower level al-Qaeda leaders since 2006 but the strikes had killed 700 civilians.

"That's a hit rate of two per cent on 98 per cent collateral. It's not moral."

His comments were made as the international community said that the absence of Asif Ali Zardari, Pakistan's president, from his country at a time when military operations against the Taliban had triggered the biggest movement of people in 62 years was a bad political misjudgment.

Mr Zardari has yet to return from a visit to Washington last week to meet Barack Obama, the US president, in spite of a growing humanitarian crisis as 1.3m refugees flee fighting against Islamist militants in the Swat valley and Malakand region. He has travelled to Libya and is en route to the UK before going to France.

Diplomats in Islamabad said the president's absence was symbolic of a wider disengagement of Pakistan's political classes with the challenges faced on the ground. It is seeking to push back an insurgency spilling out of the border regions into North-West Frontier province and Punjab.

"If this is the fight for survival of Pakistan, it doesn't look like that," said one western diplomat. "There is a lack of engagement on the part of the political classes."

The president also drew criticism within Pakistan.

"This is no time for the president to be out of the country when people are dying, there is a refugee crisis and there is a war," said Ghazala Minallah, a civil society campaigner.

Pakistan's military said it faced stiff resistance from militants in the Swat valley but was succeeding in driving them back. The army said it had killed 751 militants at the cost of the lives of 29 soldiers.

Government officials fear that up to 200,000 civilians are trapped in Mingora, the administrative headquarters of Swat.