ANCHORAGE, Alaska — The U.S. Geological Survey says a significant earthquake has jolted the ocean floor near Alaska's remote Aleutian Islands.

The agency says in a preliminary report that the magnitude-6.1 quake struck the seismically active but sparsely populated island chain at 4:49 a.m. Sunday.

It was centered at a depth of about 39 miles, and 35 miles southwest of the island of Atka, which lies about 1,100 miles southwest of Anchorage.

The West Coast and Alaska Tsunami Warning Center says no tsunami is expected from the quake.

A police dispatcher in the town of St. Paul — some 400 miles away — says he felt no tremors and has heard no reports of damages or injuries.