Twitter sued the Department of Homeland Security Thursday in U.S. District Court in San Francisco. | AP Photo Twitter sues over feds’ request to unmask owner of @ALT_USCIS account

Twitter is suing the federal government over what the company says is an unconstitutional effort to expose the identity of the creator one of the many anti-Trump "alt" federal agency accounts that popped up soon after President Donald Trump was sworn in.

On Thursday, the short-message social-media site sued the Department of Homeland Security in U.S. District Court in San Francisco, seeking to void a summons that a Customs and Border Protection agent sent to the company demanding that it turn over records identifying those behind the "@ALT_USCIS" account — a Twitter handle apparently used by one or more employees of the U.S Citizenship and Immigration Services.


"Defendants may not compel Twitter to disclose information regarding the real identities of these users without first demonstrating that some criminal or civil offense has been committed, that unmasking the users’ identity is the least restrictive means for investigating that offense, that the demand for this information is not motivated by a desire to suppress free speech, and that the interests of pursuing that investigation outweigh the important First Amendment rights of Twitter and its users," Twitter's attorneys wrote.

The complaint doesn't identify the person behind the account, but the American Civil Liberties Union said it will represent that person in the litigation.

"The right to anonymously speak out against the government is clearly protected by the First Amendment. We are pleased to see Twitter standing up for its users’ rights," said ACLU attorney Nathan Wessler. "To unmask an anonymous speaker online, the government must have a strong justification. But in this case the government has given no reason at all, leading to concerns that it is simply trying to stifle dissent."

CBP's summons warned Twitter not to notify the owner of the account, but the company did so after CBP said it did not intend to obtain a court order blocking such disclosure. The social-media company complains that the summons it received was issued under a federal law that pertains to investigations of illegal importation of merchandise.

A spokesperson for Customs and Border Protection did not immediately respond to a request for comment.

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Twitter's suit notes that the "ALT_USCIS" account is one of dozens that have cropped up in recent months, particularly after the Trump administration moved to assert greater control over official government agency Twitter accounts.

The court complaint the company filed uses the term "unmask," or some variant thereof, 10 times — an apparent attempt to troll the White House, which is currently trying to deflect criticism about the Trump campaign's contacts with Russian agents by drawing attention to Obama national security adviser Susan Rice's reported decision to request the "unmasking" of the names of U.S. individuals incidentally captured in US. intelligence surveillance of foreign targets.

Twitter's court filing also throws another elbow at Trump by citing, among a slew of legal precedents, the litigation over fraud claims related to the Trump University real estate seminar program. Last week, a judge approved a $25 million settlement of those cases.

Twitter is represented in the case by a high-powered legal team from Washington law firm Wilmer Hale, including former Bill Clinton Solicitor General Seth Waxman.

Paperwork attached to the suit shows that the summons to the firm was requested by a special agent in CBP's Office of Professional Responsibility in Washington and approved by the special-agent-in-charge at CBP's Miramar, Florida, office.