United States President Donald Trump is asking an appeals court to restore his power to block critics on Twitter.

Key points: Judge ruled last month blocking users violated First Amendment

Judge ruled last month blocking users violated First Amendment Grounds for appeal not listed

Grounds for appeal not listed Trump twitter account unblocked seven plaintiffs in case

Government lawyers representing Mr Trump and White House social media director Dan Scavino filed paperwork to appeal a federal judge's ruling last month that said blocking people from the @realDonaldTrump account violates the First Amendment.

The paperwork did not list grounds for the appeal.

Mr Trump and Mr Scavino's lawyers did not immediately respond to messages.

Jameel Jaffer, a lawyer for the seven plaintiffs who sued, said the @realDonaldTrump account had unblocked the seven plaintiffs on Monday.

"We're pleased that the White House unblocked our clients from the President's Twitter account but disappointed that the Government intends to appeal the district court's thoughtful and well-supported ruling," Mr Jaffer said in an email.

Judge Naomi Reice Buchwald made clear in her May 23 ruling that people have a right to reply directly to politicians who use their accounts as public forums to conduct official business.

The decision — the most prominent in a string of similar cases against public officials — could mark a turning point for constituents interacting with government employees on social media.

Ms Buchwald's ruling stopped short of ordering Mr Trump to unblock users.

Donald Trump's regularly blocks his critics on Twitter. ( Twitter )

"Two days shy of the one year anniversary of my blocking, @realDonaldTrump has unblocked me," Rebecca Buckwalter-Poza, who had sued Mr Trump, tweeted.

"Theory: He just didn't want to give me the paper anniversary gift."

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Mr Trump built his campaign on early morning tweet storms and hashtag-worthy slogans.

Since taking office, he's turned his account into a virtual megaphone — boasting about accomplishments, jeering opponents and dismissing critical media coverage as "fake news" to his more than 52 million followers.

Author Stephen King and model Chrissy Teigen are among those who have been blocked from Mr Trump's Twitter account.

Ms Buckwalter-Poza, the judicial affairs editor for Daily Kos, said she's confident she and other Trump critics will win again on appeal.

"We're still right, and they're still wrong," she said.

AP