A blast ripped through a street in the busy Latin Quarter of central Paris on Wednesday, causing the facade of a design school popular with foreign students to collapse, blowing out windows and starting a huge blaze.

At least 16 people were injured, including seven who are in a critical condition, police said.

The Paris prosecutor’s office said it was too early to say what caused the blast.

But the local deputy mayor, Edouard Civel, referred to a gas explosion in a Twitter post and witnesses told BFM TV there had been a strong smell of gas moments before the blast.

Television images showed rubble from the Paris American Academy strewn across the Rue Saint-Jacques and smoke rising from at least two nearby buildings that were ablaze.

“I heard a huge explosion,” local bar employee Khal Ilsey said. “And as I was leaving the restaurant, I saw flames at the end of Rue Saint-Jacques.”

The blast occurred at 4:55pm local time (1455 GMT), just as workers were heading home.

More than 200 firefighters were involved in the emergency response. Television images showed firefighters manning hoses and aiming jets of water at the blaze while a plume of thick black smoke billowed into the sky.

Paris police chief Laurent Nunez said later that the blaze had been brought under control.

Rue Saint-Jacques in the 5th arrondissement of central Paris leads from the Notre-Dame de Paris Cathedral to the Sorbonne University and the Val de Grace military hospital and is a few blocks from the popular Jardin du Luxembourg.

The area is usually packed with tourists and foreign students in the early summer.

“I was at home writing … I thought it was a bomb,” said art historian Monique Mosser, adding that many of the windows in her building had been blown out by the blast’s shockwave.

“A neighbour knocked on the door and told me that the fire brigade were asking us to evacuate as quickly as possible. I grabbed my laptop, my phone. I didn’t even think to take get my medication.”

In 2019, a gas leak caused an explosion which killed 4 people and injured 66 in the 9th arrondissement. In April 2019, a fire broke out in the Notre-Dame Cathedral, destroying much of the roof and causing other damage before it was extinguished.