French police are hunting for a "dangerous" suspect who deposited a paper bag containing a device that exploded on Friday, wounding 13 people on a busy pedestrian street in the city of Lyon. France's counter-terrorism prosecutor, Remy Heitz, said an investigation has been opened for "attempted murderer in relation with a terrorist undertaking" and "criminal terrorist association". He said no group has claimed responsibility for the explosion yet. Regional authorities said 13 people suffered mostly minor injuries but 11 were still in the hospital on Saturday morning. Video surveillance showed the suspect heading toward the centre of Lyon on a bike on Friday afternoon, wearing a cap and sunglasses that partially hid his face. The man arrived on foot, pushing his bike along the pedestrian-only Victor Hugo street, then left paper bag on a concrete block in the middle of the street near a bakery. He immediately returned to his bike and left by the same path. One minute later, the explosion shattered the glass of a refrigerator in the bakery, Mr Heitz said. Investigators at the scene have found screws, metallic balls, batteries, a triggering device that can be used remotely and plastic pieces that may have come from the explosive device. French President Emmanuel Macron called the explosion an "attack" during a live interview on Friday about the European Parliament elections that continue until Sunday. Police issued an appeal for witnesses on Saturday and released a photo of the suspect from video surveillance. They described the man as "dangerous". Mr Heitz said police would release more photos soon. Local authorities said security has been enhanced in France's third-largest city, including with more police and military patrols. The women's World Cup soccer tournament is scheduled to start in France on June 7 and Lyon will host the semifinals and then the July 7 final. After the explosion, Interior Minister Christophe Castaner sent instructions for Lyon authorities to strengthen security for "public sites and sporting, cultural and religious events". On Victor Hugo street, police removed their cordon around the explosion area and the atmosphere Saturday was almost back to normal with people doing their shopping – except for the chalk lines drawn by forensics on the ground. "It was scary," said Gisele Sanchez, owner of a cloth shop in front of the bakery. Large wood planks protected her shop window, which was hit by the blast. Police found screws, metallic balls and batteries in her shop but Ms Sanchez was able to reopen on Saturday morning. France is jittery after a spate of attacks in recent years, some of them deadly, carried out by people ranging from extremist attackers to mentally unstable individuals. Five people were killed on December 11 in an attack on the Christmas Market in Strasbourg, in eastern France. The alleged attacker, Cherif Chekatt – who was killed by police – had pledged allegiance to ISIS.