A young Haitian man who accused Uruguayan troops serving as UN peacekeepers in Haiti of sexually assaulting him last year has testified in Montevideo before a judge investigating the case.

The scandal erupted in September 2011 after mobile phone video images circulated on the internet appeared to show soldiers serving with the UN mission sexually assaulting the man, then 18, in the southern Haitian town of Port-Salut.

Six Uruguayan marines were indicted last year on charges of disobeying orders and dereliction of duty. The first charge is punishable by four months to four years of prison, and the second by up to three years in prison.

The alleged victim Johnny Jean on Thursday gave his deposition to Alejandro Guido, the judge overseeing the investigation.

Jean, who has spoken to Al Jazeera about the alleged attack, was accompanied by two US attorneys, his mother and a Haitian government representative.

He also came with a translator, as he only speaks Creole.

"The entire investigation is based on a very brief, fragmented film of poor quality filmed on a mobile phone and the testimony of this young Haitian," Raul Oxandarabat, spokesman for Uruguay's supreme court, said.

Jean's attorneys said they had proof that the assault took place.

"What they did to this young man is absolutely horrible. (...) What I saw in that video turned my stomach," said one of the lawyers, Edwin Marger. "They deny it. I don't know how they can."

"Johnny was examined by doctors. They said he had been assaulted, and that evidence will be presented in this case," Marger said, adding that some evidence had been given to the investigating judge. "This is not about money, but about justice," he said.

The scandal has prompted protests outside the Uruguayan base at Port-Salut and calls for the withdrawal of UN forces from Haiti.

Eleuterio Fernandez Huidobro, Uruguay's defence minister, earlier said that the incident had caused "a lot of damage" to the reputation of its armed forces, which provide about 2,400 peacekeepers worldwide, mostly in Haiti and the Democratic Republic of Congo.

Deployed since June 2004 under Brazilian leadership, the United Nations Mission for the Stabilisation of Haiti has troops from 18 countries, but most are from Latin America.

After the January 2010 earthquake, the force grew from about 9,000 troops to 12,250 but UN Secretary General Ban Ki-moon has said the time has come to begin a gradual drawdown.