The Pentagon has officially extended some military benefits to same-sex partners, but said provisions such as medical coverage would not be offered to gay troops' spouses due to legal barriers.
US Defence Secretary Leon Panetta, who is due to retire this month, said the decision stemmed from the repeal 17 months ago of a ban on openly gay recruits serving in the military.
"It is a matter of fundamental equity that we provide similar benefits to all of those men and women in uniform who serve their country," Panetta said in a statement.
"Today, I am pleased to announce that after a thorough and deliberate review, the department will extend additional benefits to same-sex partners of service members."
The move, which defence officials had signaled last week, will provide same-sex partners with military identity cards, hospital visitation rights, access to youth and education programmes and financial compensation in the event their military spouse dies, a Pentagon memo said.
"Extending these benefits is an appropriate next step under current law to ensure that all service members receive equal support for what they do to protect this nation," Panetta said.
The number of same-sex couples affected by the decision is about 17,000 in the armed forces, including 5,600 active duty service members.
Panetta acknowledged that federal law, which defines marriage as between a man and a woman, remained an obstacle to extending the full array of military benefits.
"One of the legal limitations to providing all benefits at this time is the Defence of Marriage Act, which is still the law of the land," Panetta said.
"There are certain benefits that can only be provided to spouses as defined by that law, which is now being reviewed by the United States Supreme Court."
Medical benefits and housing allowances could not be provided to same-sex partners, because of the federal law, defence officials said.
Pentagon lawyers are still reviewing whether housing on military bases could be granted to same-sex spouses without violating the act.