A major magnitude-7.1 earthquake has hit central Mexico, killing at least 119 people, trapping an unknown number of others beneath toppled buildings and forcing thousands of people into the streets in panic.

Key points:

• Majority of deaths reported in state of Morelos
• President Enrique Pena says 27 buildings collapsed in Mexico City
• Epicentre was near Atencingo in central state of Puebla

Mexico City Mayor Miguel Angel Mancera said at least 44 buildings collapsed in the capital, one of the world's biggest cities, and between 50 and 60 people had been pulled alive from rubble.

TV images showed a multi-storey building with a middle floor collapsed as sirens blared from first responders rushing to the scene.

Other video showed cars crushed by debris, and the side of a government building coming apart and falling onto the street as bystanders screamed.

Many people fled into the streets, and electricity and phone lines were down in parts of the capital.