It's an unlikely sight at one of the biggest US military bases: young families lining up and waiting patiently outside a warehouse for free gifts to slip under the Christmas tree.

Times are tough as much for military families as for anyone else in America this Christmas, making donated toys for the children -- from teddy bears and Barbies to board games and bicycles -- more welcome than ever.

"Like any other family, it's hard times," said Sergeant Israel Taylor, 32, an Iraq war veteran now assigned to the military honor guard at Arlington national cemetery, and the father of two children, aged eight and two.

"Luckily, being in the military, we have programs like USO that provide stuff like this to help out, so that's always good to have," he said as his daughter Tracie yearned for a Monster High goth fashion doll.

USO, or the United Service Organizations, is a non-profit organization that offers recreational and morale-boosting services to US military personnel worldwide.

Its metropolitan Washington branch is behind Project USO Elf, which has grown fast in response to the recession that hit the United States hard in 2008 and never really left. This year, it's catering to a record 1,600 children.

"The economic downturn hits military families just like it does anybody else," Crystal Benton, a USO spokeswoman, told AFP as families collected bright red bundles of presents from volunteers in Santa hats and green elf costumes.

Last year USO and the Capital Area Food Bank got together to supply free groceries to about 300 families at Fort Belvoir, a virtual city-within-a-city south of Washington that supports 31,000 military and civilian personnel.

And last month, USO had to put a 1,400-family cap on its annual "turkey for the troops" giveaway of the bird that is the obligatory centerpiece of Thanksgiving dinner.

Military pay in the United States is at an all-time high, but for enlisted personnel and their families in particular, it is by no means a fortune -- especially in the face of rising food, fuel and day-care costs.

-- 'We budget for it' --

Monthly paychecks range from $1,467 for a private to $2,728.50 for a staff sergeant or, in the navy, a petty officer first class, topped up in some locations with cost-of-living allowances.

Nationally, the median household salary was $4,200 a month in 2009, according to the most recent data from the US Census Bureau. (At the top end of the military pay scale, a major-general gets just over $10,000 a month.)

Many of the toys donated to Project USO Elf come from big Pentagon contractors such as Raytheon, the world's biggest maker of guided missiles, which came through with 50 employee-assembled bicycles.

DynCorp International, a private military contractor, contributed 1,600 iPod Touch music players -- one for every child, regardless of age -- which typically retail for $199 each.

The transient nature of military life -- as well as prolonged absences when the principal breadwinner is gone abroad for months on end -- adds to the financial burden.

"If you're moving every two to three years, it's more challenging for a spouse to find a second-income job when they are competing with people who are struggling to find their first income for their family," Benton said.

Cara Coan, a mother of three who followed her Marine Corps husband to Washington from "the middle of nowhere" in Twentynine Palms, California, knows the experience first-hand.

"Budget," she said, explaining how she deals with the cost of living. "We budget for it... It's been quite the adjustment. We're very thankful to be on base now (after six weeks in a hotel). That helps a lot."

Sergeant Jessica Wells, 28, a Marine for nearly a decade -- and the mother of two, aged seven and five, who want a microscope and Backyardigan toys for Christmas -- said a strong sense of solidarity helps, too.

"I think there's a lot of support of military members, so it helps out quite a bit more than in the civilian population," said Wells, who is also grateful that the military can pick up the doctor's bills for her ailing husband.