A D.C. court on Thursday sentenced two Turkish-American men to a year and a day in prison for their roles in an attack on protesters in May that strained U.S.-Turkey relations amid local outcries for justice.

Sinan Narin, 45 of McLean, Virginia, and Eyup Yildirim, 50, of Manchester, New Jersey, have been in custody since being arrested in June. To quickly resolve the issue, their lawyers and the U.S. attorney agreed to the one-year-and-a-day sentence for assault and conspiracy, with credit for time already served.

Narin and Yildrim also were sentenced to three years of supervised release and ordered to pay $100 to a crime victims fund.

D.C. Superior Judge Marisa Demeo approved the sentencing agreement, but also sought to impose a restitution order for Yildirim to pay $1,800 to a victim who was shown being kicked by Yildirim in video footage of the melee.

Yildirim’s lawyer, Mark Schamel, argued against the restitution order, noting it was not part of the original agreement. A court panel will decide Monday whether Judge Demeo’s order exceeded her authority.

The U.S. attorney and Metropolitan Police identified at least 17 other people — most of them members of Turkish President Recep Tayyip Erdogan’s security team — in the May 16 attack on peaceful protesters outside the Turkish ambassador’s residence. Narin and Yildrim were pro-Erdogan supporters who punched and kicked the pro-Kurdish demonstrators with the security officers.

The Turkish Embassy defended the attack, saying it was provoked by supporters of Kurdish militants.

Last month, The Wall Street Journal first reported that charges had been dropped against 11 of the Turkish security officers — four in November 2017 and seven in February, with the dates coinciding with meetings between senior Trump administration officials and their Turkish counterparts.

Federal and municipal authorities declined to comment on the dropped charges.

Arrest warrants on assault charges for four security personnel and two Canadian citizens remain open.

On Thursday, the D.C. Superior Court room was filled to capacity by parties on both sides of the case.

Before sentencing, three victims read statements on their injuries and lasting trauma from the attack.

“I was on the ground and getting kicked in the head,” said Lucik Usoyan, who suffered a concussion and said she has experienced memory loss and anxiety since the attack. “If police officers were a moment late, I’d be dead.”

Murat Yasa, who was shown being kicked by Yildirim, also suffered a concussion and required stitches in his nose.

“I felt like they were beating me forever and wouldn’t stop until I was killed,” said Mr. Yasa, who is more than 60 years old.

Abbas Azizi, also over the age of 60, said between three and four people kicked him in his head, chest, neck and back. He needed stitches in his head.

Mr. Azizi said he has had significant memory issues since the attack.

Across the courtroom, Yildirim rolled his eyes.

The judge acknowledged the case’s complexity, saying it is a straightforward criminal matter that has drawn international attention because “of the context in which it occurred.”

“This is so shocking because it is the opposite of our democratic values,” Judge Demeo said.

Victims and their supporters expressed disappointment with the sentence.

“This decision should worry every American,” said Aram Hamparian, executive director of the Armenian National Committee of America. “Today’s light sentences — on top of the administration dropping most charges and failing to seek any extraditions of Erdogan’s bodyguards — threatens to chill the free exercise of the First Amendment rights of Americans of Armenian or any other heritage to protest the actions of a foreign government.”

“This was a significant attack and we are disappointed,” said Agnieszka Fryszman, an attorney representing at least 15 victims and considering a civil lawsuit. “At the same time we all appreciate the work of the prosecution. They’ve done a terrific job.”