NEW YORK -- The U.S. Army will make an exception to a decades-old rule and allow a Sikh doctor to serve without removing his turban and cutting his hair, an advocacy group said Friday.

Capt. Kamaljeet Singh Kalsi is the first Sikh to be allowed to go on active duty with a turban, beard and unshorn hair in more than 20 years, according to the New York-based Sikh Coalition.

The decision does not overturn an Army policy from the 1980s that regulates the wearing of religious items, Acting Deputy Chief of Staff Maj. Gen. Gina Farrisee wrote in a letter to Kalsi dated Thursday and posted online by the Sikh Coalition.

Instead, the Army's decision follows a long-standing practice of deciding such requests on a case-by-case basis, the letter said. Farrisee said the Army had weighed Kalsi's request against factors such as "unit cohesion, morale, discipline, safety and/or health."

There's no indication that the overall policy is being reconsidered, said Army spokeswoman Jill Mueller, adding that she could not confirm that the Army had reached a decision in the case until she received word from her superiors that Kalsi himself had been notified.

But Sikh Coalition director Amardeep Singh said he was hopeful the Army would announce a full policy shift.

"This bodes well for the future," he said. "My guess is the Army's going to be seeing a lot more Sikhs requesting to be a part of the Army. ... This issue is not going away."

The 32-year-old Kalsi, of Riverdale, N.J., is an emergency room doctor. He promised to serve in the Army in exchange for help paying for his medical training. A second, similar case - that of Capt. Tejdeep Singh Rattan - will be decided after he receives the results of his dental board exams, Amardeep Singh said.

A number of members of Congress wrote to U.S. Defense Secretary Robert Gates in August asking him to allow the men to serve while wearing the turban, beard and unshorn hair required by their faith.

"We do not believe that any American should have to choose between his religion and service to our country," the letter said.