U.S. military chaplains are authorized to perform same-sex marriages in jurisdictions that recognize such unions, the Pentagon said Friday.

The new guidance took effect on Sept. 20, when the ban on openly homosexual or lesbian individuals serving in the Armed Forces - known as Don't Ask, Don't Tell - officially ended.

"A military chaplain may participate in or officiate any private ceremony, whether on or off a military installation, provided that the ceremony is not prohibited by applicable state and local law," Under Secretary of Defense Clifford Stanley said in a memo released Friday.

"Further," the memo added, "a chaplain is not required to participate in or officiate a private ceremony if doing so would be in variance with the tenets of his or her religion."

Participation by military chaplains in a same-sex wedding "does not constitute" Defense Department support for gay marriage, the Pentagon said.

Same-sex unions are legal in Vermont, Massachussets, Connecticut, Iowa, New York, New Hampshire and the District of Columbia.

With the end of Don't Ask, Don't Tell, gay rights activists have set their sights on repeal of the 1996 Defense of Marriage Act, which defines marriage as a union between a man and a woman.