Earlier on Thursday, after British Prime Minister Theresa May met with German Chancellor Angela Merkel and French President Emmanuel Macron in the margin of the European Union summit in Brussels, a spokesperson of Downing 10 claimed that "the UK, Germany and France reaffirmed that there is no plausible explanation other than that the Russian state was responsible".
Macron said investigators are trying to establish how the suspect obtained the gun used in the attack in Trebes and nearby city of Carcassonne, where officials say the 26-year-old hijacked a vehicle and claimed his first victim.
He had also been under surveillance by security services in 2016-2017 for links to the radical Salafist movement, Paris prosecutor Francois Molins said.
A police union official says officers have stormed a supermarket in southern France and killed a suspect who took hostages there.
Speaking in Brussels, President Emmanuel Macron said the incident appeared to be a terrorist attack.
On Friday morning, an armed man broke into the store in the town of Trebes, firing shots and killing 2 people.
He said one woman connected to Lakdim had been arrested.
He later drove the vehicle to the supermarket and immediately opened fire upon people, killing two before taking several others as hostages.
"We're going to do everything possible to help passengers", Pepy said, adding that the SNCF's national headquarters and regional offices would be closed in order to free up personnel.
Another witness, an employee of the supermarket's butchery identified only by his first name Jacky, told Europe 1 radio he "heard people shouting and big 'boom'".
Lakdim then shot and wounded a police officer who was out jogging with colleagues before driving to nearby Trebes where he burst into the Super U supermarket.
One supermarket worker said some shoppers had escaped from the building after the gunman burst in.
BFM TV reported that he claimed allegiance to Islamic State.
"If we don't do anything, the government won't back down", CGT chief Philippe Martinez said.
Abdeslam, a French citizen born and raised in Brussels, went on trial in Belgium last month.
"It was referring to the USA -led coalition that has been carrying out airstrikes against IS in Syria and Iraq since 2014. Unfortunately the threat is everywhere", Collomb told reporters in Trebes.
Macron described the attacks as an act of "Islamic terrorism", but said the claims by Daesh* terrorist group of being behind the attacks have not been confirmed yet.
Nearby Beziers is one of the biggest cities controlled by the far-right, while the smaller Languedoc town of Lunel further east became a breeding ground for many French jihadists who travelled to Syria to fight. He was killed by security forces after a more than 30-hour stand-off.