PARIS — A powerful explosion tore through a bakery in central Paris on Saturday morning, killing at least two firefighters and leaving smoke, flames and scattered debris in its wake, the authorities said.
The police and city authorities said the blast, which occurred on Rue de Trévise, was believed to have been caused by a gas leak.
Christophe Castaner, the interior minister, initially said two civilians and two firefighters were among the dead. He later corrected the toll on Twitter to two dead from the Paris Fire Department. About 200 firefighters had battled the blaze, and photos on social media showed people being rescued with a ladder after the explosion.
Eric Moulin, a Paris Fire Department spokesman, told reporters that at least 36 people had been injured by the explosion, including 12 seriously; three firefighters were among them. At least 24 others suffered minor injuries, he added.
Rémy Heitz, the Paris prosecutor, said that the blast had been “manifestly accidental.” He told reporters at the site, “First there was a gas leak, then the arrival of the firefighters, followed by an explosion that caused the fire.”
The explosion came as Paris and other cities around France were bracing on Saturday for a ninth week of protests by the “Yellow Vests” movement, which had been marked by episodes of violence and vandalism of high-end stores. But there was no indication that the explosion on Saturday had anything to do with the protests.
The Yellow Vests are protesting the social and economic policies of President Emmanuel Macron, whom they consider to be out of touch with their everyday needs. But the demonstrations have also come to express a wider discontent with the political and media elites.
On Saturday, demonstrations were expected in Paris and in Bourges, a much smaller town in central France that some protest organizers had chosen because it was closer to the regions where many of the Yellow Vests live.
After the large explosion in Paris, pictures on social media showed a blackened store front at the corner of Rue Trévise and Rue Sainte-Cécile, in the 9th Arrondissement of Paris, with windows blown out, debris strewn around the street and fires still burning. Other images showed damaged buildings and broken windows stretching for several blocks.
Mr. Castaner said later on Saturday that the situation was “under control” but that he was still “under shock” after seeing the site of the explosion. About 100 police officers were sent to the scene.
The explosion occurred on a residential street in an area of Paris that is also well known to tourists, with many hotels and attractions nearby, including the Grévin wax museum and the Folies Bergère music hall.
One person wrote on Twitter: “Woke up to the apartment building shaking as if I had never left California … not an earthquake, but an explosion on Rue de Trévise not even a mile from me.” Another person wrote of hearing screams.
Residents told French television that firefighters had been responding to reports of a gas leak in the neighborhood and were ordering residents to turn off their gas supply and stay inside when the explosion occurred.
Anne Hidalgo, the mayor of Paris, said on Twitter that all those who had been affected by the explosion, who were in need of shelter or who were looking for information about the blast could seek help at the 9th Arrondissement Town Hall.
Many apartment buildings in Paris use gas for heating and other purposes, but deadly explosions because of leaks are rare. In 2016, an explosion caused by a gas leak in the 6th Arrondissement tore off the roof of an apartment building and wounded 17 people.