Twitter Inc. Thursday filed a lawsuit against the Trump administration after the government tried to force the social media platform to reveal the identity of one of its users.

* Updated: On Friday, the Department of Homeland Security dropped its attempt to reveal the owner of the account, prompting Twitter in turn to drop its lawsuit.

On March 14 Homeland Security’s Customs and Border Patrol issued a summons to Twitter to reveal the IP address, phone number and mailing address of the account @ALT_USCIS. The account provides critical comment on U.S. citizenship and immigration services, and is claimed to be the creation of rogue former and past federal immigration employees. It has defined itself as being “official inside resistance.”

@ALT_USCIS has been consistent in its criticism of Trump’s immigration policies, including his plans for a wall on the Mexican border and the restriction of travel in the U.S. from people coming from several mostly Muslim countries. One example of such criticism is this January tweet: “Fact: More than 40% of illegal aliens in the US are Visa overstays from other developed countries not sounding like MEXICO #TheResistance.”

Twitter objected to the government’s demand, citing the First Amendment. “Permitting CBP to pierce the pseudonym of the @ALT_USCIS account would have a grave chilling effect on the speech of that account in particular and on the other ‘alternative agency’ accounts that have been created to voice dissent to government policies,” Twitter stated in the suit.

This is not just about our account. This is about all twitter users whether you agree with our view point or not. #WeAreAltGov #resist

— ALT? Immigration (@ALT_uscis) April 7, 2017

The American Civil Liberties Union plans to file its own suit against CBP. “To unmask an anonymous speaker online, the government must have a strong justification,” ACLU attorney Nathan Freed Wessler told the New York Times. “But in this case the government has given no reason at all, leading to concerns that it is simply trying to stifle dissent.”

We’re glad Twitter is pushing back. We’ll be going to court to defend this user’s right to anonymous speech. https://t.co/tqj5XrNvgn

— ACLU National (@ACLU) April 6, 2017

Following Donald Trump’s inauguration, a slew of anti-government accounts appeared on the social media site, some of which claimed to be run by disgruntled government employees. Created in January, @ALT_USCIS resembles other ant-government accounts such as @Alt_CDC and @Alt_Labor.

Image: Esther Vargas via Flickr