Everyone knows President Trump loves Twitter, but it seems the microblogging site isn’t a fan of his administration. The company is suing the U.S. government over demands that it reveal the identity of a user behind an anti-Trump account.

According to Twitter’s suit, a US Customs and Border Protection (CBP) agent named Adam Hoffman sent the firm a summons requesting information that could unmask the person behind Twitter account “@ALT_uscis” – one of several “alt” government accounts that appeared just after Trump took office.

@ALT_uscis is believed to be run by a rouge member of the US Citizenship and Immigration Services. It’s unclear which Tweets the CBP has objected to, but, as you would expect, many of the account’s posts are criticisms of Trump’s immigration policies. The @ALT_uscis bio reads: "Immigration resistance . Team 2.0 1/2 Not the views of DHS or USCIS. Old fellow drank russian soup. #altgov."

The CBP’s summons requested records that included IP logs, associated phone numbers, and mailing address. Twitter states that it informed the account holder of the demand, and told the CBP it would fight the summons in court.

Twitter argues that there is no legal reason for the government to demand details of the account. “Defendants have not even attempted to meet that burden. For these and other reasons discussed below, Twitter respectfully requests that this Court declare the summons unlawful and enjoin its enforcement," the lawsuit reads.

Twitter invoked First Amendment rights to protect the identity of @ALT_uscis: “The rights of free speech afforded Twitter’s users and Twitter itself under the First Amendment of the U.S. Constitution include a right to disseminate such anonymous or pseudonymous political speech," the company wrote in its lawsuit.

The American Civil Liberties Union (ACLU) is expected to represent the person or persons behind the @ALT_uscis account.