Update: The Federal government has abandoned its unmasking efforts, and Twitter has dropped the lawsuit. The original version of the story is below.

Twitter Inc. has sued to block an attempt by federal officials to unmask the person or people behind @ALT_USCIS, one of the so-called “alternative agency” Twitter accounts critical of Trump administration policies that have popped up over the past few months.

Like many of the alternative agency accounts, @ALT_USCIS claims that it is run by an individual currently employed by the federal government, in this instance the U.S. Citizenship and Immigration Services. According to the complaint filed Thursday by a team at Wilmer Cutler Pickering Hale and Dorr, the account attracted more than 32,000 followers in less than two months of existence with its mix of political commentary and often critical observations about the agency.