A woman stands at the entrance of the closed Jewish Museum in Brussels
A woman stands at the entrance of the closed Jewish Museum in Brussels shortly after the shootings in MayReuters

An alleged accomplice of the gunman Mehdi Nemmouche who is accused of shooting dead four people in a Jewish museum in Brussels in May has been arrested by police.

The 27-year-old from Marseille who was arrested on Tuesday, allegedly met the alleged former Isis militant Nemmouche in jail, and has been ordered into detention, a law enforcement source told AFP.

The man has a criminal record, and is named in a European arrest warrant.

Four other people arrested as part of the police operation, in which weapons were seized, have been released.

A Paris appeals court will rule on whether the man should be turned over to Belgian authorities, a move he has resisted.

Nemmouche, 29, a French citizen of Algerian origin was arrested in Marseille shortly after May's attack, in which a gunman entered the Jewish museum in central Brussels and shot dead a French woman, an Israeli couple, and critically wounded a Belgian staff member, who later died in hospital.

He was seized after being spotted on a coach from Brussels.

He is currently being held by authorities in Belgium, and his lawyers have declined to seek bail, which they strongly deny as an admission of guilt.

The attack is being treated as a terrorist incident by Belgian authorities.

Nemmouche's lawyers claim that there is no evidence tying him to the scene of the crime, and that authorities have tried to smear him by claiming he helped to guard western hostages when fighting for Isis in Syria.

Authorities believe that Nemmouche was radicalised in jail, before travelling to Syria.

Prosecuters argue that a revolver and Kalashnikov found in Nemmouche's possession when he was arrested resembled those carried by the man caught on CCTV carrying out the attack.

They claim that Nemmouche was carrying a camera on which a recording was found in which someone with a voice resembling Nemmouche's claimed responsibility for the attack.

He is also alleged to have been carrying an Isis flag.

The attacks sparked fears that jihadists with combat experience on the battlefields of Syria could commit deadly terror attacks on their return to Europe.