A powerful earthquake has shaken south and central Mexico, causing people to flee buildings and office towers in the country's capital, and setting off quake alert systems.

Crowds of people gathered on central Reforma Avenue in Mexico City as the ground shook.

The U.S. Geological Survey put the quake's preliminary magnitude at 7.5 and said its epicenter was 2 kilometers southeast of Pinotepa in Oaxaca state. It had a depth of 43 kilometers.

A magnitude 7.1 earthquake in central Mexico on Sept. 19 left 228 people dead in the capital and 369 across the region.

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