Dylann Roof, the alleged white supremacist accused of shooting dead nine black churchgoers and injuring three others in South Carolina last year, has been declared mentally competent to stand trial, a judge ruled on Friday (25 November).

A 16-hour hearing was held behind closed doors on Monday (21 November) and Tuesday (22 November) after his defence team raised concerns earlier in the month surrounding Roof's understanding of the proceedings filed against him.

US District Judge Richard Gergel said he had given their concerns careful consideration, reviewing testimony from a psychiatrist who evaluated the 22-year-old, as well as arguments from lawyers.

While he found Roof to be mentally competent, Judge Gergel declined to comment further on his mental state so as not to jeopardise the defendant's right to a fair trial.

Jury selection for the high-profile case will commence on Monday (28 November).

Despite Roof's indications that he would enter a guilty plea in return for life imprisonment, prosecutors are seeking the death penalty for his alleged assault on the Mother Emanuel AME church during an evening bible study class in June 2015.

Roof faces 33 federal charges, including nine counts of hate crimes resulting in death, nine counts of murder, obstruction of religion, and firearms charges.

His trial is due to begin in January 2017.

The church where the killings took place was a historic place of worship for the black community, and Roof's federal indictment accused him of wanting to " increase racial tensions across the nation".

He is also accused of seeking "retribution for perceived wrongs he believed African Americans had committed against white people".

After the shootings, photos emerged online of the accused holding the Confederate battle flag, sparking a backlash against the emblem, which to many is a symbol of slavery.

The murders saw an outpouring of national grief and caused South Carolina's governor Nikki Haley to remove the Confederate flag from the statehouse grounds.

The nine congregants Roof is accused of murdering ranged in age from 26-year-old Tywanza Sanders to 87-year-old Susie Jackson, and also included 41-year-old Clementa Pinckney, the church's pastor and a South Carolina state senator.