PARIS, May 25 (Xinhua) -- A man, believed to be behind the blast that injured scores in the southern French city of Lyon, was still unidentified and police operation was underway to determine his whereabouts, Paris prosecutor Remy Heitz said on Saturday.
The suspect appeared in security camera footage partially masked with dark sunglasses and a cap, making hard for investigators to identify him, Heitz told reporters.
He was wheeling a bicycle to Victor Hugo street, a pedestrian popular street where he had left a bag outside Brioche Doree bakery at 17:27 local time (1527 GMT). One minute later, the package which contained screws, batteries and remote triggering device, exploded.
Paris prosecutor confirmed that 13 people were suffering injuries. Eleven victims were evacuated to hospitals.
"A first appeal for witnesses has been launched. All the testimonies are being examined. New photographs of the individual will be released soon," he said.
"All the means have been deployed to allow the perpetrator's identification and his arrest," he said, adding that no claim of responsibility has so far been made for the blast.
His counter-terrorism section has opened an investigation into "attempt of assassination in relation with terrorist enterprise".
Earlier on Saturday, Justice Minister Nicole Belloubet said it was too early to say whether the blast was a "terrorist act".
"Anti-terrorism division of the Paris prosecutor office has opened an investigation for criminal and terrorist conspiracy. But, it is necessary to await the results of the on-going investigation," Belloubet told BFMTV news channel.
"In the light of these results we can then qualify this act," she added.
Following the explosion whose motive remained unidentified, Interior Minister Christophe Castaner said he "sent vigilance instructions to all prefects to enhance the security of public sites and sporting events, cultural and religious".
France remains top target of terrorist cells due to its military intervention in Iraq, Syria and the Sahel region.
A wave of attacks, claimed by the Islamic State, had broken the calm several times in France. The bloodiest terror attack took place in Paris on November 2015, when a series of explosions and shootings left 130 victims.