Department of Homeland Security Secretary Janet Napolitano on Thursday clarified that gay and lesbian couples are to be considered “family relationships” in immigration proceedings.

“In an effort to make clear the definition of the phrase 'family relationships,' I have directed ICE [Immigration and Customs Enforcement] to disseminate written guidance to the field that the interpretation of the phrase 'family relationships' includes long-term same-sex partners,” Napolitano said in a letter.

Napolitano was responding to a July letter signed by 84 members of Congress, including House Minority Leader Nancy Pelosi and New York Rep. Jerrold Nadler, asking her to clarify where gay couples stood under the Obama administration's new policy of shifting priority on certain deportation cases.

Steve Ralls, a spokesman for Immigration Equality, a group working to protect the rights of binational gay couples, told The San Francisco Chronicle that this is “one of the very first times LGBT families have been recognized within federal immigration policies.”

Unlike heterosexuals, gay immigrants married to a U.S. citizen are not allowed to apply for citizenship based on their relationships under the Defense of Marriage Act (DOMA), the 1996 law which bans federal agencies from recognizing the legal marriages of gay and lesbian couples.

Pelosi welcomed the move, saying it would “provide a measure of clarity and confidence to families dealing with separation in immigration cases.”

Nadler added: “I am thrilled that the Obama Administration has taken to heart my concern about the need to explicitly protect LGBT immigrant families from being torn apart by needless and unwarranted immigration enforcement actions. I thank Secretary Napolitano for listening and supporting a policy that protects all American families, both straight and LGBT. With the written guidelines that I requested and which will be issued by ICE, federal immigration officials will finally have the clear direction they need to make responsible and compassionate decisions on family ties in immigration cases.”

Two lawsuits are currently pending challenging the constitutionality of DOMA as it relates to the issue; one was filed in New York and the second in California.