A free speech group says President Donald Trump continues to block dozens of people from his Twitter account although a court ruled his actions violate free speech enshrined in the First Amendment of the U.S. Constitution.

The Knight First Amendment Institute at Columbia University in New York sent a letter to the Justice Department Friday saying the president is still blocking 41 people from his @realDonaldTrump account.

The group contends almost all of the people in question were blocked after they posted unfavorable tweets about Trump or his policies.

"The First Amendment prohibits the president from blocking Twitter users simply because they've criticized him," said Knight Institute attorney Katie Fallow.

U.S. District Judge Naomi Reice Buchwald in New York ordered Trump on May 23 to restore to his account to a group of seven people who had filed a lawsuit. The plaintiffs were unblocked in June. Buchwald did not directly order Trump to unblock the 41 users referred to in Friday's letter.

Buchwald's order to unblock the plaintiffs came after she ruled that comments posted on Trump's account, or those of other government officials, were public and that blocking their viewpoints violates their constitutional right to free speech.

Trump has used his Twitter account, which has nearly 54 million followers, to promote his agenda, announce policy decisions and to denounce his critics. Blocking his critics prevents them from directly responding to his tweets.

The White House has not commented on the letter but the Justice Department said in an appeal Tuesday Buchwald's ruling was "fundamentally misconceived."

Trump's account "belongs to Donald Trump in his personal capacity and is subject to his personal control, not the control of the government," the appeal said.