By Harriet McLeod

CHARLESTON, S.C. (Reuters) - A South Carolina judge on Thursday extended for another week a temporary order sealing court documents and silencing lawyers and others involved in the case of the slayings of nine people at a historic black church in Charleston last month.

Ninth Circuit Judge J.C. Nicholson cited concern about "any graphic pictures of the victims dead on the floor of the church or 911 calls that might have recorded the sounds of victims."

Suspected gunman Dylann Roof sat quietly in a gray striped prison suit and shackles next to a public defender during a 30-minute hearing in which the judge set July 11, 2016, for the start of the trial.

The 21-year-old white man was arrested a day after the June 17 killings and charged with nine counts of murder in what authorities say was a racially motivated massacre.

A defense attorney told the hearing Roof's competency to stand trial is not an issue and that he has a high school certificate.

His attorneys waived bond, but the judge said he was denying it anyway. Prosecutors have not said if they will seek the death penalty and Roof has yet to enter a plea.

The South Carolina Press Association had challenged Nicholson's decision last week to issue a gag order on potential trial participants as well as banning the release of documents including 911 police dispatch calls, coroner's reports and witness statements.

Nicholson extended the ban until a hearing on July 22 to allow other interested parties, including relatives of the victims, to be heard.

Nicholson issued the order last Friday citing "substantial pre-trial publicity" that could jeopardize Roof's right to a fair trial.

On Thursday, however, he said the police photos and 911 calls were his main concern. "Frankly at this stage, the court does not think pre-trial publicity is a problem," he said.

The press association argued the public had a right to know about the case and that the judge's order was too broad.

Thursday was Roof's first appearance in court since a magistrate's bond hearing on June 19, in which he appeared by video standing in a nearby holding room and victims' family members expressed grief and their forgiveness of him.

A grand jury indicted Roof on nine murder charges in the killings of Bible-study members at Charleston's Emanuel African Methodist Episcopal church including its pastor, the Rev. Clementa Pinckney, who was also a state senator.

Roof was also indicted on three counts of attempted murder and a firearm charge. He also faces possible federal hate crime charges.

After the murders a website linked to Roof surfaced containing a racist manifesto and showing him in photos posing with Confederate flags, a banner from the American Civil War widely considered a symbol of slavery.

(Reporting by Harriet McLeod; Writing by David Adams; Editing by Mohammad Zargham and James Dalgleish)