A strong earthquake struck southwest Mexico on Monday, shaking buildings as far away as the capital and prompting people to stream out of their offices onto the street, though there were no reports of serious damage.

The U.S. Geological Survey said the tremor registered magnitude 6.3 and centred 175 km (108 miles) east-south-east of the tourist resort of Acapulco, not far from where a much more powerful earthquake struck last month.

It felt strong, but thank God nothing happened to us. Everyone went back (inside) but people are still paranoid about the other one which felt much stronger, said 30-year-old Esteban Vite in Mexico City's Roma neighbourhood.

Thanks to the authorities, things are better built.'

Marcelo Ebrard, the mayor of Mexico City, said there were no initial signs of damage from a first flyover of the city, and telephones were still working. However, one local radio station said the airport had closed. The city's underground metro was still working, the mayor added.

Phone lines went down during the March 20 earthquake of 7.4 magnitude. That tremor unleashed panic in the capital and damaged hundreds of buildings in the states of Guerrero and neighbouring Oaxaca in southwest Mexico.

The latest quake was measured at a depth of 7.6 miles (12.3 km) and located near the border of Guerrero and Oaxaca.

There were no initial reports of damage in Guerrero, a spokesman for local emergency services said.

Mexico City was devastated by an 8.1 magnitude quake in 1985 that killed thousands of people.

(Reporting by Cyntia Barrera and Mica Rosenberg; editing by Christopher Wilson)