Earlier in the day workplaces across Mexico City held readiness drills on the anniversary of the 1985, 8.0 magnitude, earthquake, which killed thousands of people.

"I'm so worried. I can't stop crying. It's the same nightmare as in 1985," said Georgina Sanchez, 52.

World championships postponed

The world para swimming and powerlifting championships to be held in Mexico City later this month have been postponed following the devastating earthquake this week, the International Paralympic Committee (IPC) said on Wednesday.

The IPC said that this was the first time it had been forced to postpone a major championship. Both events were due to start on Sept. 30. with 1,400 athletes, officials and staff involved.

"As a result of this tragedy, we are in full agreement that the immediate focus of the Mexican authorities should be on prioritising recovery and rebuilding for the Mexican people and not organising two major international sport events," IPC President Andrew Parsons said in a statement.

"I know the postponement of both championships will be disappointing news to all the athletes who were set to take part, however these are unique circumstances and quite simply this is the right thing to do at the moment."