MEXICO CITY - A magnitude 7.1 earthquake stunned central Mexico on Tuesday, killing at least 120 people as buildings collapsed in plumes of dust. Thousands fled into the streets in panic, and many stayed to help rescue those trapped.

Dozens of buildings tumbled into mounds of rubble or were severely damaged in densely populated parts of Mexico City and nearby states. Mayor Miguel Angel Mancera said buildings fell at 44 places in the capital alone as high-rises across the city swayed sickeningly.

The quake is the deadliest in Mexico since a 1985 quake on the same date killed thousands. It came less than two weeks after another powerful quake caused 90 deaths in the country's south.

Mexico City's mayor said at least 30 died in the capital, and officials in Morelos state, just to the south, said 54 died there.

At least 26 others died in Puebla state, state disaster prevention chief Carlos Valdes said. Governor Alfredo del Mazo said at least nine died in the State of Mexico, which also borders the capital.

Officials in Oaxaca reported one quake-related death in that southern state, which is far from the quake's epicenter.

Mancera said 50 to 60 people were rescued alive by citizens and emergency workers in Mexico City. Authorities said at least 70 people in the capital had been hospitalized for injuries.

The federal interior minister, Miguel Angel Osorio Chong, said authorities had reports of people possibly still trapped in collapsed buildings.

At one site, reporters saw onlookers cheer as a woman was pulled from the rubble. Rescuers immediately called for silence so they could listen for others who might be trapped.

A dust-covered Carlos Mendoza, 30, said that he and other volunteers had been able to pull two people alive from the ruins of a collapsed apartment building after three hours of effort.

"We saw this and came to help," he said. "It's ugly, very ugly."

Alma Gonzalez was in her fourth-floor apartment in the Roma neighborhood when the quake pancaked the ground floor of her building, leaving her no way out - until neighbors set up a ladder on their roof and helped her slide out a side window.

Gala Dluzhynska was taking a class with 11 other women on the second floor of a building on trendy Alvaro Obregon street when the quake struck and window and ceiling panels fell as the building began to tear apart.

"There were no stairs anymore. There were rocks," she said.

The U.S. Geological Survey said the magnitude 7.1 quake hit at 2:15 p.m. EDT and was centered near the Puebla state town of Raboso, about 76 miles southeast of Mexico City.

-AP