Buildings collapse as powerful earthquake rocks Mexico

At least 27 buildings in Mexico's capital have collapsed in the earthquake, including multi-level residences. Magnitude 7 earthquakes are regarded as major catastrophes and often cause widespread heavy damage.

Crowds erupted in applause when rescue workers pulled a survivor out of one collapsed building. They were immediately silenced, however, as rescuers listened closely to find others trapped in the rubble.

People poured onto the streets as high-rise buildings swayed sickeningly in the city of 20 million people. The earthquake happened in the early afternoon, just hours after city authorities had conducted an earthquake drill.

Authorities have released tentative death tolls in the surrounding states, but no official figures were available in the capital. The earthquake caused most of its damage in the center and south of the sprawling city.

The disaster stirred memories of a 1985 earthquake that killed more than 10,000 people in the city. Emergency officials warned people not to smoke in the streets to avoid igniting gas leaking from ruptured pipes.

The quake came on the anniversary of the 1985 disaster and less than two weeks after another tremor left 90 dead in the country's south. Seismologists said this quake was not an aftershock of the previous one.

Fires broke out in many buildings across Mexico City, which is one of the world's largest metropolises. Electricity and phone lines were down in many parts of the city.