Strong earthquake strikes off northwestern Mexico

A strong 6.9-magnitude earthquake struck off Baja California in northwestern Mexico yesterday, shaking buildings as far away as San Diego, California, and raising fears of a small tsunami.

The US Geological Survey said the quake struck inside the Sea of Cortez, 122 kilometres from the town of Santa Isabel on the Baja California peninsula and was 10 kilometres deep. The figures were revised from its initial estimates.

There were no initial reports of deaths or serious damage.

Baja California, home to desert and mountains, is sparsely populated.

The quake was felt strongly in San Diego just across the border from Mexico and City Hall was evacuated, local media said.

"It felt very calm, there was barely a vibration," said hotel receptionist Graciela Alvarado at a motel in the town of Caborca, in the Mexican state of Sonora, across from Baja California.

Local authorities and the USGS warned there was a risk of a small, localised tsunami in the area but no official tsunami warning for the main Pacific coastline.

"There's a very high risk this could occur," said Baja California emergency services director Alfredo Escobedo.

The area attracts US tourists.