WASHINGTON (AFP) - A powerful 6.0-magnitude quake rumbled off the coast of Alaska early on Thursday, according to the US Geological Survey (USGS), but there were no immediate reports of casualties or damage.

The epicenter of the quake was 102km from Craig, Alaska, and more than 1,000km from Vancouver, in the Canadian province of British Columbia, the USGS said.

The West Coast and Alaska Tsunami Warning Centre said there was no risk of the earthquake generating a tsunami.

An even larger 7.5-magnitude quake struck off Alaska in the same area earlier this month, generating a local tsunami and rattling homes as far away as the state capital Juneau, some 330km away.

The Jan 5 temblor also caused no casualties or damage.