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By Phil Stewart and Adrian Croft
BRUSSELS, Feb 21 (Reuters) - NATO officials are strongly considering a proposal to keep Afghan forces at their peak strength of 352,000 until at least 2018, as opposed to current plans to cut the force by a third after 2015, alliance officials said on Thursday.
Backers say the proposal, disclosed to a small group of reporters during NATO talks in Brussels, would send a crucial signal of enduring support for Afghanistan and bolster Afghan confidence after the United States and its allies declare their long, unpopular war in the country over at the end of 2014.
But it could also cost allies billions of dollars more at a time when budget pressures are already squeezing defense spending and forcing Western nations to make tough choices about military priorities.
NATO Secretary-General Anders Fogh Rasmussen, asked about the proposal, stressed that no final decisions had been made. But he also argued that paying for the larger force was possible and preferable to fielding foreign forces.
"I feel confident that we will be able to finance Afghan security forces of that size," he told a news conference.
The United States this year is providing $5.7 billion of the $6.5 billion cost to field the Afghan forces, which are nearly at peak strength. Other NATO members are providing $300 million and the Afghans are paying for $500 million of that total.
In recent months, top U.S. and NATO commanders have expressed growing confidence about the ability of Afghan forces to take the lead successfully in all operations starting this Spring and to take full responsibility for security at the end of 2014, despite a still resilient insurgency.
But U.S. officials, including President Barack Obama's nominee to lead the U.S. military's Central Command, General Lloyd Austin, have strongly backed the idea of keeping the Afghan forces at peak strength longer.
Austin, who will head Central Command if confirmed by the Senate, said at his Senate confirmation hearing last week that a more robust Afghan force, while more costly, would "hedge against any Taliban mischief" following America's longest war.
A NATO official, speaking on the sidelines of a meeting of NATO defense ministers, cautioned that the larger issue at hand was ensuring confidence among Afghans that the international community was committed to Afghanistan.
"This confidence thing ... it isn't (Afghan) confidence in the fight, it's not confidence in battle," the official said.
"It really is, are we (Afghans) still going to have a job after 2014? We heard the force was going to be 228,000. What happens to me?"
MEMORIES OF 1992
Memories are still fresh in Afghanistan about how foreign aid dried up after the Soviets' humiliating defeat in their decade-long war against mujahideen fighters in 1989.
Moscow continued to prop up the communist government of Mohammad Najibullah but when the Soviet Union collapsed two years later, the aid vanished, Najibullah was ousted in 1992 and civil war engulfed Afghanistan.
"If I have a clear vision about 2015, then I just keep doing my job, I keep staying focused. I keep training my soldiers," the official said, speaking on condition of anonymity.
"If I think that this thing may run out in December 2014, and the narrative of 1992 gets played, as unrealistic and as completely different as the circumstances may be, now what I might be doing is actually trying to siphon money off from my soldiers. I may be trying to buy a house in Dubai."
"I may be trying to figure out how I am going to take care of my family after 2014 when the well runs dry."
Obama is weighing up how many troops to keep in Afghanistan after 2014. Proposals under consideration range up to around 9,000. He announced on Feb. 12 a plan to withdraw 34,000 U.S. troops by early 2013, or about half the current total of 66,000.
It remains unclear if NATO allies will cut numbers by a similar proportion over the next year, but the NATO official said allies were aware of the need to help keep the focus on supporting the Afghans during the peak summer fighting months.
"All the troop contributing nations are very much appreciative of what we want to do in the summertime and what we don't want to do in the summertime," the official said.
"What we don't want to do in the summertime is incur an undue amount of friction and turn the focus to be closing bases and redeploying, when really the focus ought to be setting the Afghans up for success in their first fighting season." (Reporting by Phil Stewart and Adrian Croft; Editing by Vicki Allen and David Brunnstrom)