SAN FRANCISCO • Twitter has sued the federal government to block the unmasking of an anonymous account that has posted messages critical of the Trump administration and claims to have ties to a government agency.

The suit sets up a potential confrontation between the Trump administration and Twitter over digital privacy, a thorny issue that has driven a wedge between the technology industry and government in the past. Twitter disclosed in a federal court filing on Thursday that it had received a summons directing it to reveal the identity or identities of those behind @ALT-USCIS, one of several alt-accounts run by people purporting to be current or former federal employees.

The account has described itself as "official inside resistance" and has said several times that the person or people using it to post messages is a current federal employee of Citizenship and Immigration Services, part of the Homeland Security Department.

Twitter said in its filing that it could not be compelled to disclose the identity or identities of whoever is behind the account. It argued that the government's directive and reasoning were unlawful, and would have "a grave chilling effect" on the speech of alt-accounts that voice resistance to government policies.

NYTIMES