Amsterdam - A "substantial" earthquake was felt in the north-eastern Dutch province of Groningen, the Dutch weather research centre KNMI said Thursday.

The spokesman for the KNMI, located in De Bilt in the central Netherlands, told Deutsche Presse-Agentur dpa it was a "relatively substantial" earthquake "approaching 3.5 on the Richter scale."

The KNMI could not yet confirm the exact size of the quake.

The earthquake was felt around 7 am (0600 GMT) in the morning. No damage has been reported.

Groningen, a predominantly rural area, is the only Dutch province where gas can be found. Gas extraction takes place on a large scale, resulting in light earthquakes every now and then. (dpa)