Lt. Col. Bryan Hilferty, an Army spokesman, said the service has taken back some 350 soldiers who had already retired from the military. But some of those could have done 20 years of duty and still be only in their late 30s. He did not know how many of the returning retirees are 60 or older.

The reason, he said, is clear: "It's the continuing demand in the service."

The Navy has 36 medical personnel and 16 chaplains who are over 60.

There is one Marine between 60 and 65 currently serving.

The Air Force has 12 chaplains over 60 and 32 medical personnel between 60 and 65.

"The rules say it's at 60 years of age when people retire," said Dov Schwartz, an Army spokesman. The Army will issue waivers allowing people who are older to serve if they have needed skills. Returning, though, is "totally voluntary," Schwartz said.