The cause of the blast that occurred in or outside a branch of the bakery chain Brioche Doree wasn't immediately clear, according to Kamel Amerouche, the regional authority's communications chief.  Authorities couldn't confirm French media reports that a small package had exploded.

The victims sustained leg injuries that weren't life-threatening, Amerouche told The Associated Press.

Live television images showed the Brioche Doree sign intact and police vans and an ambulance on the street, which had been cordoned off. The central area, the Presqu'ile, lies between the Rhone and Saone rivers that run through France's third-largest city.

Resident Jean-Pierre, who lives above the bakery and didn't give his last name, told BFMTV the noise from the explosion was "deafening" but it didn't cause the walls to shake. He said one window shattered and there was some debris on the street.

French President Emmanuel Macron called it an "attack" during a live interview about the European Parliament elections that run through Sunday, but the president of greater Lyon, David Kimelfeld, urged calm.

"We must remain prudent and wait for the analysis of the circumstances and not panic the Lyon population," Kimelfeld said on BFMTV.

Earlier, French officials said eight people were wounded, but later lowered the figure to seven.

The women's World Cup soccer tournament is scheduled to start in France on June 7. Lyon will host the semifinals, and then the final on July 7.

French Interior Minister Christophe Castaner said in a tweet that he has sent instructions for Lyon authorities to strengthen "the security of public sites and sporting, cultural and religious events."

Macron sent his thoughts "to the injured and their families."

French Prime Minister Edouard Philippe cancelled an appearance at a European elections-related meeting in Paris over the Lyon explosion.