An apartment building collapse in downtown Bombay (search) on Tuesday, killed 11 people, injured 17 and left more than a dozen trapped under the rubble, a top city administrator said.

The dilapidated four-story structure, which was more than 100 years old, was home to 16 families, said Johnny Joseph, Bombay's municipal commissioner. The building caved in while most residents were sleeping, he said.

At least 47 people were rescued, but at least 20 were still trapped, he said.

Eleven of the injured died on their way to the hospital, said P.H. Shingare, the dean of the hospital. Most the 17 people undergoing treatment at the hospital had head injuries, broken bones or internal bleeding, Khote said.

Rescue officials also evacuated residents of two buildings next to the collapsed structure, while local residents helped by clearing wood and tin debris. Rescue work was hampered because the building could be approached only through a narrow, crowded lane.

Building collapses are common in Bombay, where more than 16,000 dilapidated buildings have been declared unsafe.

City officials repeatedly slap evacuation notices on the buildings, but residents, mostly low-income families, ignore them.

Chief Minister Vilasrao Deshmukh (search), the elected head of Maharashtra (search) State of which Bombay is the capital, ordered an investigation into the accident.

"We will take action against whoever is found guilty," he said.