WASHINGTON — Supreme Court Justice Anthony Kennedy has temporarily blocked Washington state officials from releasing the names of people who signed a ballot measure on gay rights.

Kennedy’s ruling today temporarily blocks a federal appeals court ruling last week that ordered the release of the names. Kennedy said his order would remain in effect while he considers a request by a pro-marriage group that asked him to reverse the appeals court ruling.

The case involves Referendum 71, a ballot initiative that asks Washington voters to approve or reject the state’s so-called “everything but marriage” law, which grants registered domestic partners the same legal rights as married heterosexuals.

Kennedy has asked state officials to file a written response in the case today.

A group called Protect Marriage Washington circulated a petition to put the law before the voters. Under the Washington state constitution, voters have the power to reject any law through the referendum process.

In September, U.S. District Judge Benjamin Settle temporarily barred state officials from releasing the identities of those who signed the referendum petitions. Settle held that releasing the names could chill the First Amendment rights of petition signers.

Gay rights supporters and open-government groups sought to disclose the names, saying that signers should be identified so the public knows who is behind Referendum 71.

The 9th U.S. Circuit Court of Appeals reversed Settle’s decision last week. The appeals court said Washington’s secretary of state can release the names and addresses of people who signed petitions calling for a public vote.

In appealing to Kennedy to intervene, Protect Marriage Washington argued that state officials had suddenly changed a long-standing practice of keeping confidential the identities of those who signed referendum petitions. The group said signers of the petition fear hostile confrontations from gay rights supporters and noted that their campaign manager had received death threats.

James Bopp Jr., a lawyer who represents the group, said releasing the names of those who signed the petition would make the group’s appeal of the 9th Circuit ruling moot.

Janelle Guthrie, a spokeswoman for Washington Attorney General Rob McKenna, said state officials were merely defending the state’s public records law.

The attorney general’s office argued in court that there’s little evidence of threats or harassment amounting to more than a few rude phone calls.