An explosion ripped through a 4-story building late Monday, killing two men and a boy, injuring several dozen people and strewing furniture and glass all over the street, police, fire officials and witnesses said.

Authorities said the blast sparked a fire, caused the building on the eastern edge of Italy's financial capital to collapse and shook other buildings as far as 400 meters (1,300 feet) away. Fire officials said about 50 people were injured.

The fire department said those killed included a young Albanian man who had been passing by, an older Italian man and a 7-year-old boy who lived in the building. It did not immediately release their names or the ages of the men.

The boy's body was found more than three hours after the blast as his mother looked on in tears.

Claudia Rosi Toletti, 58, a high school German language teacher who lives on the same street, one block over, said she was in her apartment with her son when she felt the explosion.

"With this story about the pope the first thing I thought about was a bomb," she said, referring to widespread anger from Muslims around the world in response to recent remarks by Pope Benedict XVI about Islam.

Milan's Fire Department said the blaze was put out about an hour after the explosion and rescue officials were combing through the ruins searching for people who might be trapped.

Fire officials said witnesses said they had smelled gas shortly before the explosion, which occurred about 8 p.m. (1800 GMT).

"There's so many people going by at that hour," Toletti told The Associated Press. "And I thought that if it had happened about 5:30 p.m. I could have been killed."

Alessandra Rossi, a 40-year-old travel agent who lives on a neighboring street, said she heard the explosion and ran out onto the street along with dozens of others.

"The front of the building had collapsed and you could see inside people's apartments," Rossi said in a telephone interview. She said furniture and glass were strewn all over the street.