Barack Obama's decision to order 17,000 more combat troops to Afghanistan signals the start of an intense debate in Nato about how to respond to the country's crisis, western diplomats and military officials say.

When he announced his decision on Tuesday night, Obama said the increase was "necessary to stabilise a deteriorating situation in Afghanistan".

His military advisers urged him to deploy as many as 30,000 extra troops. The president said military means alone would not solve the problem.

The US government is conducting a review of policy towards Afghanistan, as is General David Petraeus, overall commander of US forces in the Middle East and Central Asia. Both reviews are likely to conclude that more emphasis should be placed on the economic, social, and political, development of the country - including corruption and the heroin trade. That, and training the Afghan security forces, costs money. But some donor countries are wary of spending more and are reneging on their promises, leaving a shortfall of billions of dollars, according to a report by the Afghan finance ministry.

Of $21bn (£14.7bn) in aid pledged at an international donors' conference in Paris last year, only $14bn was new money, leaving a shortfall of $7bn, the report says.

A senior British defence official yesterday described the operation against the Taliban as "strategically a stalemate". Though Britain shares the US view that there is no long-term military solution - and both agree that talks with Taliban leaders will have to be pursued - there are concerns about a shortage of combat troops. Britain and the US are increasing pressure on their Nato partners to deploy more troops and equipment, notably helicopters. Italy and Germany have indicated they are prepared to deploy more forces. But a number of governments do not share the view expressed by Obama and British ministers that Afghanistan could collapse into a failed state, allowing the Taliban and al-Qaida to become the kind of threat that they were before 9/11.

With Nato casualties reaching record levels, a UN report this week said war-related civilian Afghan deaths increased by nearly 40% to 2,118 last year.

While it said "anti-government elements" were responsible for 55%, a quarter of all civilian casualties - 552 people - died as a result of US and Nato air strikes.

Polls suggest foreign troops are becoming increasingly resented in Afghanistan, and that the main cause of this is the number of civilians killed.