An earthquake measuring 6.6 magnitude struck off the west coast of Mexico on Thursday, the US Geological Survey(USGS) said.

The quake jolted 215 km southwest of Tomatlan, Jalisco, Mexico at 18:07 GMT. The epicenter, with a depth of 10km, was initially determined to be at 18.6 degrees north latitude and 107.0 degrees west longitude.

The Pacific Tsunami Warning Center (PTWC) did not issue a tsunami warning. "Based on all available data ... There is no tsunami threat from this earthquake," said PTWC in a statement following the quake.

Luis Felipe Puente, Mexico's national coordinator for civil security, said that security protocols had been activated in 125 municipalities and no casualties or damages had been reported till now.

Additionally, the civil security bureau for the state of Jalisco sa that they were monitoring infrastructure and buildings across the state, while recommending that people remain calm.

The earthquake was initially registered at 6.9 in magnitude but later was revised down to 6.6, according to the USGS. It is the first important tremor reported in Mexico in 2016.