The official, who spoke on condition that he not be named because President Barack Obama has yet to unveil his fresh strategy on Afghanistan, said non-military assistance could rise to three times the current roughly $450 million a year.

Military aid, now running at $300 million a year, could also rise, although by a lesser amount, the official added, saying that conditions could be attached to the defense funds but not to the development money.

The steps aim to win greater Pakistani cooperation to address what is seen as a major weakness of the current US approach in Afghanistan: the existence of safe havens in Pakistan from which insurgents launch attacks in Afghanistan.

If it boosts development aid to Pakistan, the White House would embrace an approach laid out by Vice President Joe Biden when he was chairman of the Senate Foreign Relations Committee and by the panel's senior Republican, Senator Richard Lugar.

Legislation backed by the two, and by the panel's new chairman, Democratic Senator John Kerry, called for giving an extra $1.5 billion a year in non-military aid to Pakistan over five years, amounting to a total of $7.5 billion.

‘The basic approach to Pakistan is the one that comes out of the ... legislation, and that is that the first thing that you have got to do with Pakistan is convince Pakistanis that you are there with them for the long term and that you don't just love them for their terrorists,’ said the official.

‘The approach in the legislation was to increase the non-military assistance dramatically to help build a more stable modern Pakistani society and government and then provide military assistance that helps them fight terrorism,’ he said.

He said the military aid was likely to come with conditions to ensure it would be used against insurgents, but said this was ‘very complicated because you don't want to end up cutting off your nose to spite your face.’

‘You might call it a bargain, rather than conditions: If you are committed to transforming your army into a capable counter-insurgency force, these are the kind of things we can do for you,’ the official said, saying assistance could include helicopters or night vision goggles.

Britain's ambassador to the United States, Sir Nigel Sheinwald, said Washington could help Islamabad ‘bear down on the rise in extremism’ in Pakistan by providing more aid.

‘If there is a more broadly based program of assistance from this country to Pakistan, focusing on the building up of infrastructure and on economic development as well as on military assistance, I think that will help,’ he told Reuters.

‘I feel like the real war on terror is not in Iraq, and it's not in Afghanistan,’ said David Kilcullen, an expert on guerrilla warfare and the author of ‘The Accidental Guerrilla,’ a study of counter-insurgency. ‘It's in Pakistan.’

‘The real conceptual issue, the real strategic decision that has to be made is: what the hell are we going to do about Pakistan? How are we going to support them? How are we going to stabilise them?’ he said.