WASHINGTON — The military is poised to extend some benefits to the same-sex partners of service members, U.S. officials said Tuesday, about 16 months after the Pentagon repealed its ban on openly gay service.

Defense Secretary Leon Panetta has not made a final decision on which benefits will be included, the officials said, but the Pentagon is likely to allow same-sex partners to have access to the on-base commissary and other military subsidized stores, as well as some health and welfare programs.

Panetta must walk a fine, legal line. While there has been increased pressure on the Pentagon to extend some benefits to same-sex partners, defense officials must be careful not to violate the 1996 Defense of Marriage Act, which forbids the federal government from recognizing any marriage other than those between a man and a woman.

An announcement is expected to come in the next several days. Officials discussed the plan on the condition of anonymity because they were not authorized to publicly speak about internal Pentagon deliberations.

Pentagon press secretary George Little declined to comment.

Officials said the military likely will require that some type of document be signed to designate the military member’s partner as a legitimate recipient of the benefits. The same-sex partners are also expected to be issued some type of identification card that would give them access to the military installations and programs.