WASHINGTON — A strong earthquake struck near the Aleutian Islands on Thursday, the U.S. Geological Survey reported.

The USGS said the quake, with a preliminary magnitude of 6.6, was located 40 miles west of Adak, Alaska at a depth of 6.2 miles. It gave the location as 1,225 west south west of Anchorage in the Andreanof Islands. The quake struck at 4:33 p.m. local time.

The report on the USGS Web site made no mention of damages or injuries.

Earthquakes with a magnitude in excess of 6.0 are capable of causing severe damage.