Twitter has pulled its lawsuit filed against the US Department of Homeland Security on Friday (7 March) after the US government withdrew a request to reveal the identity of an anti-Trump account. On Thursday, Twitter sued the DHS in response to the administration's attempts to unmask @ALT_USCIS, one of the numerous "alternative" Twitter accounts that popped up since President Trump's inauguration and are claimed to be run by current or former members of various government agencies.

Like most "alt" accounts, this one claims to be run by a current government employee at the US Citizenship and Immigration Services (USCIS) office and was fiercely critical of Trump's controversial immigration policies.

In the original lawsuit filed on Thursday, Twitter revealed that the Customs and Border Protection, a division of the DHS, issued a summons to the social media company on 14 March demanding the user names, account login, phone number, mailing addresses and IP addresses associated with @ALT_USCIS. The agency cited a federal law that is typically used to obtain records about imported merchandise.

Twitter fired back with a lawsuit to block the order arguing that the CBP was "abusing a limited-purposed investigatory tool" and violates the First Amendment. The company also said the government cannot compel Twitter to disclose its users' identities without meeting multiple tests first including proving that a criminal or civil offense has been committed.

Less than 24 hours later, Twitter dropped its charges against the DHS after the CBP withdrew its summons.

"On April 7, 2017, counsel for Defendants from the Department of Justice contacted counsel for Twitter to advise that US Customs and Border Protection has withdrawn the summons and that the summons no longer has any force or effect," Twitter's motion to dismiss reads.

"Because the summons has now been withdrawn, Twitter voluntary dismisses without prejudice all claims.

Revelations of the CBP's summons, however, quickly sparked massive backlash from privacy, freedom of speech and civil liberties advocates including the American Civil Liberties Union said it would join the court fight and represent the @ALT_USCIS user.

"We want to thank @twitter and @aclu for standing up for the right of free anonymous speech," the @ALT_USCIS account tweeted. "Thank you resistance for standing up for us." The account tweeted that it will be "taking a break" from tweeting following the summons and lawsuit.

We want to thank @twitter and @aclu for standing up for the right of free anonymous speech. Thank you resistance for standing up for us. https://t.co/6PdwZIJ2xP — ALTð Immigration (@ALT_uscis) April 7, 2017

We are taking a break! The past few days have been extremely difficult and full of anxiety. Thank you again America! — ALTð Immigration (@ALT_uscis) April 7, 2017

ACLU attorney Esha Bhandari said in a statement: "The speed with which the government buckled shows just how blatantly unconstitutional its demand was in the first place. Speaking anonymously about issues of the day is a longstanding American tradition, dating back to when the framers of the Constitution wrote under pseudonyms. The anonymity that the First Amendment guarantees is often most essential when people criticize the government, and this free speech right is as important today as ever."

Multiple senators also questioned the CBP's actions as well.

In a letter to CBP's acting commissioner Kevin McAleenan, Democratic Senator Ron Wyden said he was "gravely alarmed" by the order and called for an internal investigation into why and how it was issued "including whether the decision involved executive branch officials outside the CBP."

"Not only was the summons blatantly inconsistent with the cited investigatory authority... it appeared to be a disturbing threat to free speech and whistleblower protections," Wyden wrote.

Republican Senators Mike Lee and Cory Gardner also wrote a separate letter to Homeland Security Secretary John Kelly inquiring about the agency's attempts to identify the anonymous Twitter account.

"Our right to free speech is enshrined in the Constitution and we must remain vigilant to ensure it is upheld—including allowing individuals to criticize their government," Gardner wrote in a Facebook post.