A strong earthquake has hit Mexico, shaking buildings and sending people running out of offices onto the streets of the capital though there were no early reports of major damage.

Mexico City mayor Marcelo Ebrard said on his twitter account there were no initial signs of serious damage and that key services in the capital, including its subway system and the international airport, were functioning.

The US Geological Survey reports a preliminary reading of 7.0 magnitude. It said the quake on Wednesday was centred in a sparsely populated mountainous area in Mexico's Michoacan state about 336km west-northwest of Acapulco.

The quake hit about 65km below the surface.

The quake followed a series of recent temblors in the region.

A powerful 7.4-magnitude earthquake struck southwest Mexico on March 20, killing two people, injuring 13 others and damaging thousands of homes.

Several hundred aftershocks have rocked southwestern and central Mexico since then, including a 6.3-magnitude quake on April 2.

People in Mexico's crowded capital -- with more than 20 million in the metro area -- are all too familiar with seismic activity and used to evacuation drills.