A tsunami warning triggered by a strong 6.8-magnitude earthquake which struck Alaska's Aleutian Islands early Friday morning has been lifted, the US Geological Survey reported.

The earthquake struck about 1:55 am (1055 GMT) some 80 miles (130 kilometres) from the town of Dutch Harbour, and there were no initial reports of injuries or damage.

The tsunami warning was in effect for coastal areas of Alaska from Unimak Pass to Amchitka Pass, but the remote area is not heavily populated.

"It's a very remote part of Alaska,", USGS seismologist Jessica Sigala told AFP.

The epicentre was approximately 1,000 miles from the state's largest city Anchorage, and an aftershock of magnitude 4.5 was felt in the region about 30minutes later.

Soon after the quake struck, the West Coast and Alaska Tsunami Warning Centre issued a tsunami warning for parts of coastal Alaska, but cancelled it within half an hour.

The Aleutian Islands sit on the Pacific Ring of Fire, often described as a horseshoe-shaped seismic belt about 25,000 miles long and the region is home to the majority of the world's earthquakes and volcanic eruptions.

In June, an earthquake with a magnitude of 7.2 struck the same area of the Aleutians Islands, which also prompted a tsunami warning.