STORY: Rescuers were searching for two missing people feared buried under the rubble of a building that partially collapsed in the explosion.

The explosion tore through Rue Saint-Jacques, which runs from the Notre-Dame de Paris Cathedral to the Sorbonne University, in the late afternoon.

Interior Minister Gerald Darmanin said that sniffer dogs had picked up a scent under the mound of masonry left strewn across Rue Saint-Jacques.

The blast destroyed the facade of a building housing the Paris American Academy design school popular with foreign students.

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.