JAKARTA, Indonesia (AP) -- A powerful earthquake hit the western Indonesian island of Sumatra early Monday, but there were no immediate reports on injuries or damage.
The U.S. Geological Survey said the 6.6-magnitude quake was centered 60 miles (100 kilometers) southwest of the city of Medan at a depth of 62 miles (110 kilometers).
Sujabar, an official at Indonesia's meteorology and geophysics agency, said it was unclear if there had been any significant damage. No tsunami warning was issued.
Phone calls to residents in Singkilbaru, an area believed to have been badly rattled by the quake, have so far gone unanswered.
Indonesia straddles a series of fault lines that make the vast island nation prone to volcanic and seismic activity.
(Copyright 2011, The Associated Press)