Photos:12 injured in East village Building explosion, collapse after workers hit gas line.

An explosion rocked a heavily traveled section of Manhattan’s East Village on Thursday, injuring at least a dozen people and leveling parts of a building, authorities said.At least three of the injured in the seven-alarm fire were in critical condition, a fire department spokesman said.

Some people may be trapped in the blaze, a law enforcement source said. Several law enforcement sources told CNN that there is no indication that this was related to terrorism all said it appeared to be a gas explosion.
The first two floors of a red-brick building at the scene appear to have crumbled, images from the scene showed.

Luca Babini, 25, said he was in his office near the building at the time of the blast.
“Everything, my shelf in my office and my computer screen fell down,” he said. “They say it was a gas leak.”

Babini said a man climbed a fire escape in an attempt to rescue people trapped in the collapsed building.

“I saw a lot of people lined up at the streets trying to help,” he said.

Towering flames and plumes of black smoke were rising from the building, which includes both apartments and businesses. Emergency personnel could be seen taking the injured away on stretchers.
At least 250 firefighters were on the scene.

The collapsed first floor appeared to house a Japanese restaurant; the building next door, with a shop specializing in French fries on the street level, was ablaze and, in later images, appeared to have collapsed.
The explosion comes just over a year after two buildings in Harlem collapsed after a gas leak last March, killing eight people and injuring dozens. The buildings were served by a 127-year-old gas main.