Grand Place in Brussels, Belgium
Grand Place in Brussels, Belgium iStock

Witnesses were to be confirmed Thursday for the Brussels trial of a Frenchman accused of shooting four people dead at a Jewish museum after his return from Syria's battlefields.

Mehdi Nemmouche, who allegedly became the first jihadist from Syria to stage a terror attack on European soil, will be tried next month along with co-defendant Nacer Bendrer.

It was not clear whether Nemmouche and Bendrer, who is also French, would appear at the hearing which court sources say is designed to finalize a list of 150 to 200 witnesses.

After their selection, the witnesses will start testifying in January when the trial gets fully underway.

"In principle, both could be there, unless they believe it is not necessary," federal prosecutor's spokesman Thierry Werts told AFP.

Nemmouche and Bendrer face charges of "terrorist murder" over the shooting on May 24, 2014 at the Jewish Museum of Belgium in the capital Brussels.

A gunman armed with an assault rifle opened fire in the museum's entrance hall, killing two Israeli tourists, a French volunteer and a Belgian museum receptionist.

Six days later Nemmouche, 33, was arrested in the southern French port city of Marseille alighting from a bus from Brussels.

Nemmouche had returned from Syria where he had been fighting with Islamist extremists, investigators allege.

Bendrer, 30, was charged as an accomplice in February 2015, two months after his arrest near Marseille with weapons, including a Kalachnikov rifle like the one used at the museum.

Bendrer was sentenced in early September to five years in prison for attempted extortion in a separate case in Marseille.

Bendrer, who was transferred to a jail in Belgium for the trial, has protested his innocence.

"My client is not a choir boy, but he has nothing to do with this matter. He is living a true nightmare," his lawyer Christine D'Arrigo told AFP.

Investigators said Nemmouche was in Syria from 2013 to 2014 where he met Najim Laachraoui, one of the men who carried out suicide bombings in Brussels on March 22, 2016, killing 32 people and wounding hundreds more.

The same Brussels cell is also alleged to have carried out the gun and bombing attacks on November 13, 2015 in Paris that killed 130 people and wounded hundreds.

The Islamic State group, which drew thousands of jihadists from Europe to parts of Syria and Iraq under its control, claimed responsibility for both the Paris and the Brussels attacks.

Nemmouche is likely to face a separate trial in France over suspicions he was among the jailers of French hostages in Syria. He was charged in connection with this case in November last year.

Born in the northern French town of Roubaix to a family of Algerian origin, he is being held in a Belgian prison.

Watching the trial closely will be the Coordination Committee of Jewish Organisations in Belgium, which has underscored the "anti-Semitic character of this attack."

The EU Agency for Fundamental Rights (FRA) reported this month that nine out of 10 European Jews believe anti-Semitism has worsened in the last five years.

Jews have been targeted in the wave of terror attacks in Europe in the last few years, including in the French city of Toulouse in March 2012, the Paris suburbs in January 2015, and in Copenhagen in February 2015.

The case, court sources said, is to resume in Brussels on January 7 when judges will be chosen in a random draw, with the full trial getting underway from January 10.