PARIS >> A fire in a Paris apartment building early Tuesday that authorities suspect was an arson attack killed seven people and sent residents fleeing to the roof or climbing out their windows to escape.

The Paris prosecutor says a woman has been detained in the initial investigation into the fire, which blazed for hours in a calm, high-end neighborhood on the city’s western edge. It choked the air with smoke and sent orange flames into the overnight sky.

One person is in life-threatening condition and 30 others were injured in the blaze, city fire service spokesman Clement Cognon told The Associated Press.

Though the fire was extinguished before dawn, Cognon said firefighters are still going door to door to ensure there are no more victims and prevent residual fires.

Firefighters rescued about 50 people, some from the roof or those who had clambered out of windows to escape the flames, Cognon said. Among the injured were six firefighters.

Emergency workers are also seeking to shore up the building that was badly damaged after flames shot out of windows stretching across the upper floors, in images of the operation released by the fire service.

“The situation was already dramatic when the firefighters arrived,” Cognon said.

Prosecutor Remy Heitz told reporters at the scene that authorities suspect it was a criminal act, though “the investigation has just begun” and it’s too early to definitively determine the cause of the fire. He said a woman who lives in the building was detained nearby. He would not provide further details on the investigation underway.

“I heard a woman screaming in the street, crying and screaming for help,” said witness Jacqueline Ravier, who lives across the street. She saw a young man blackened by smoke and a woman motionless on the ground. She said flames were shooting out for hours from the top of the building and smoke-covered victims were fleeing.

She said shaken residents were brought to her building and the one next door while firefighters continued to fight the flames. “We feel the smoke,” she said. “What’s surprising is how long it lasted.”

The building is on Rue Erlanger in the 16th arrondissement, one of the most high-end and calmest districts of Paris. It is close to the popular Bois de Boulogne park and about 1 kilometer (less than a mile) from the Roland Garros stadium that hosts the French Open tennis tournament and near the Parc de Princes stadium that’s home to Paris Saint-Germain, the country’s top soccer team.

More than 200 firefighters and emergency workers were involved in the operation, Paris police said, and the street was blocked off. Neighboring buildings were also evacuated.

The fire comes a month after a deadly explosion and blaze linked to a gas leak in a Paris bakery.