A devastating gas explosion rocked the Latin Quarter of Paris on Tuesday, causing a massive fire that engulfed several buildings and left at least seven people in critical condition. Nine others were also injured, according to Paris police.

The blast occurred around 11:30 a.m. local time on Rue Saint-Jacques, a busy street that connects the Notre-Dame Cathedral and the Sorbonne University. The explosion was so powerful that it shattered windows and collapsed the facade of one building, where witnesses said an American language school was located.

“The explosion was extremely violent,” said Florence Berthout, the mayor of the fifth district of Paris, where the incident happened. She added that the cause of the blast was still under investigation, but it was likely due to a gas leak.

Firefighters rushed to the scene and battled the flames for hours, while police cordoned off the area and urged people to avoid it. Interior Minister Gerald Darmanin said he was closely following the situation and thanked the emergency services for their efforts.

The explosion was a reminder of a similar incident that occurred in January 2019, when a gas leak triggered a blast that killed four people and injured 66 in another central Paris district.

The Latin Quarter is one of the oldest and most popular areas of Paris, known for its historic monuments, lively cafes and student population. It attracts millions of tourists every year, who come to enjoy its cultural and intellectual heritage.