A Sikh U.S. Army captain has been granted a long-term religious accommodation to wear a beard, turban and uncut hair in uniform, a decision supporters hailed on Friday as a landmark that could help other religious Sikhs to serve in the military.

Captain Simratpal Singh received the accommodation in a memorandum from Assistant Army Secretary Debra Wada dated March 30. The memo spelled out certain limitations and said the Army was working to develop uniform standards for soldiers who receive such waivers.

The accommodation for Singh is the first for an active-duty Sikh soldier since the Pentagon took steps two years ago to give individual troops greater latitude to wear turbans, head scarfs, yarmulke and tattoos as part of their religion.

The Pentagon's move sought to make it easier for Muslims, Sikhs, Jews, Wiccans and others to follow the tenets of their faith while serving in the U.S. military. But advocacy groups say the process remains difficult.

The accommodation for Singh, a West Point graduate and Army Ranger, was granted only after he sued to prevent the service from requiring him to undergo extensive testing to ensure that his beard and hair did not interfere with his helmet or gas mask.

Even as his court case was pending, Singh passed a routine gas mask test with his unit. In barring the extensive testing, U.S. District Judge Beryl Howell said it made little sense since 100,000 soldiers had been allowed beards for medical reasons.

Advocates say Singh is the first active duty Sikh soldier to be permitted to begin wearing a turban, long hair and beard even though he had previously served without them. Singh followed Army grooming standards when he entered the military academy at West Point but regretted it and sought an accommodation last year.

"My faith ... is an integral part of who I am. I am thankful that I no longer have to make the choice between faith and service to our nation," Singh said in a statement issued by the Sikh Coalition.

Amandeep Sidhu, one of Singh's attorneys with McDermott Will & Emery, called the Army decision "a step in the right direction" but added "we are not satisfied with the U.S. military's arduous, piecemeal approach to this issue, which forces all observant Sikhs to seek individual religious accommodations."

Singh's legal team also filed a federal lawsuit this week on behalf of three other Sikh service members seeking a religious accommodation.