A strong earthquake has hit off the coast of El Salvador. The quake, which had a preliminary magnitude of 6.6, according to the US Geological Survey (USGS), sent frightened residents running out of their homes in the predawn hours.

The epicenter was about 28km (17 miles) south-southeast of La Libertad, a suburb of the regional capital, Santa Tecla. The depth was 65km (40 miles).

The earthquake was felt strongly in the capital, San Salvador, on Thursday morning. People left their homes with flashlights, and power was knocked out in at least some areas, AP reported.