Afghanistan could end up fighting Taliban insurgents with a national army and police force two-thirds the size envisaged, if plans discussed on Friday by NATO defence ministers, trying to balance security needs with budget cuts, gain traction.
The Afghan security force is due to grow to a peak of 352,000 by October, part of a hugely expensive drive to beef up their strength to deal with Taliban insurgents and allow the bulk of Western combat forces to withdraw by the end of 2014.
The effort is largely funded by the United States, at a cost of $11.6 billion for this year alone, at a time when the U.S. Department of Defense is suffering huge cuts to its budget.
While recognising it will be many years before Afghanistan is able to pay for its own security, NATO states are keen to avoid recurring costs of such magnitude after 2014, so have been considering options for a much smaller future force, with the aim of reaching agreement at a summit in Chicago in May.
NATO diplomats said U.S. Defense Secretary Leon Panetta had suggested a long-term target size for the police and army of 227,000, while French Defense Minister Gerald Longuet told reporters France would be happy with a figure around 230,000.
A senior U.S. defense official said the plan remained to build the force up to about 350,000, the size seen as necessary to give the Afghan military the internal support capabilities it will need to carry out operations on its own.
Then there may be a levelling off or a drawing down, the U.S. official said.
He said experts from the International Security Assistance Force would travel to NATO soon to brief the allies on the size and cost options of different force levels.
The official said the final numbers would be based on both efficiency - you can't go too low before you begin to take too high a risk - and the sustainability, the price tag of different options.
Diplomats and NATO officials said there were concerns about the dangers of building up such a large force and then cutting it back.
The problem is: what are they going do? said one diplomat. You don't want large numbers of armed unemployed.
NATO said it was still some way from a decision.
We discussed what could be a long-term sustainable size, but no decision has been made, NATO Secretary-General Anders Fogh Rasmussen told a news briefing. We agreed we will engage in a consultation process leading up the summit in Chicago.
Longuet said the key issues were how to fund the Afghan security forces and what to do with trained fighters not needed after cutting back the size of the force. There was a danger they could turn to crime or insurgency, he said.
NATO's Rasmussen said the alliance was also making new plans to address possible infiltration of the Afghan Army's ranks by Taliban insurgents.
All partners agreed to task our military authorities to develop a plan to counter, or rather to strengthen countering such infiltration ... before the end of February he said.
We have already taken a lot of steps, but in the light of recent events we agreed to strengthen those efforts.
Those concerns were highlighted last month after the Afghan Taliban said it had recruited an Afghan soldier who shot dead four French soldiers in an incident that prompted France to decide to pull out its troops early.
Officials say even the smaller Afghan security force could cost $4-5 billion a year to maintain, including about $1.1 billion from non-U.S. contributors.
The United States alone, which provides the bulk of the 130,000 international troops in Afghanistan, currently spends $130 billion in Afghanistan annually.
However, many military experts worry that limiting funding for the Afghan police and army could undercut hard-fought gains of the 11-year U.S.-led intervention in Afghanistan, and the Kabul government has warned that outside backers must not force it to choose between security and development.
Friday's discussion came after Panetta worried many Afghans and surprised Washington's allies Wednesday by suggesting the U.S. combat mission in Afghanistan would end in 2013, the first time Washington had floated such a deadline.
Thursday, Panetta stressed U.S. troops in Afghanistan would remain combat-ready as the United States winds down its longest war. But he said the troops would largely shift to a train-and-assist role as Afghan forces take responsibility for security before an end-2014 deadline for full Afghan control.
His comments came soon after British media published excerpts of a classified U.S. report saying that the Taliban, backed by Pakistan, remained confident of regaining control in Afghanistan despite a decade of NATO efforts.
(Additional reporting by Marine Hass; Editing by Jon Boyle)