The pair were attacked by a man, aged around 30, who reportedly shouted Allahu Akbar, before he fatally stabbed the women outside the Saint-Charles train station on Sunday afternoon.

Authorities said video surveillance footage showed the assailant attacked the first victim, then fled — only to return and kill the other woman. One of the victims reportedly had her throat slit.

It emerged on Monday that the two victims were not just known to each other, but were cousins, reports in France said. Both were students aged 20. France's counter-terrorist prosecutor François Molins later confirmed the victims were related at a press conference in Marseille.

On has been named as Laura by L'Express news site. She was in her second year of a nursing degree at a university in Lyon and had travelled to Marseille for the weekend to celebrate her birthday.

She came from the Lyon suburb of Rillieux-la-Pape, according to RTL radio, which described her as being “very involved in charitable work”.

The town's Mayor Alexendre Vincendet tweeted a message of support for the victim's family and friends. Flags hanging outside the Town Hall would be folded as a mark of respect and a minute's silence would be held on Monday, the mayor said.

Her cousin, named Mauranne, who was also killed was also a student. She was undertaking a medicine degree at university in Marseille and was originally from the village of Eiguilles near Aix-en-Provence.

The village's mayor Robert Dagorne said residents were traumatised by what had happened and called for a vigil outside the Town Hall on Monday evening t remember the victim.

While terror group Isis have claimed responsibility for the double stabbing French authorities say there is no confirmation the killer had any link to the Middle East group and the French interior ministry said they could not yet confirm the attack was motivated by terrorism.

While France has been hit by a string of terror attacks in recent years there have also been deadly incidents which investigators concluded were motivated more by the attacker's psychological disorders than terrorism, notably when a man rammed his car into a bus stop in Marseille last August.

It has emerged that Sunday's black-clad attacker, who was shot dead by soldiers on patrol at the station, was known to police after being arrested for a string of minor offences. Reports say he had been arrested in Lyon on Friday for theft but had been released.

Prosecutor Molins confirmed the attacker had been arrested seven times since 2005 and had given seven different identities.

The prosecutor said that when he was arrested in Lyon the attacker had handed over a Tunisian passport belonging to an Ahmed H. But investigators were still trying to confirm whether this is indeed the real identity of the knifeman.

The attacker was not known to French intelligence services and was not on their terror watch list. According to Prosecutor Molins the attacker was unemployed, divorced and a history of taking hard drugs.