Three strong earthquakes, of between 6.5 and 6.8 magnitude, have struck off the coast of the Canadian province of British Columbia, according to the United States Geological Survey.

All the quakes occurred in less than an hour on Sunday night.

There were no immediate reports of casualties or of any damage from the earthquakes.

A 6.6 magnitude quake struck first, at 10.39 pm local time.

The quake hit at a depth of 33 km, about 190 km southwest of Port Hardy, a town on the northeast end of Vancouver island.

A 6.8 magnitude quake and a 6.5 magnitude one occurred in succession shortly afterwards.

Geophysicist Amy Vaughan said that there were possibly some smaller quakes as well as some aftershocks.