Strong earthquake hits western Afghanistan

LONDON -- A powerful 6.3-magnitude earthquake struck western Afghanistan early Sunday, the U.S. Geological Survey said.

The quake, which was centered about 30 kilometers (18 miles) north-northwest of Herāt, followed a series of powerful tremors that killed more than a thousand.

"This earthquake was preceded by three other M 6.3 earthquakes in the previous days," USGS said in a statement. "One M6.3 occurred on October 11th and two others occurred about 30 minutes apart on October 7th."

Sunday’s earthquake was registered at a depth of 6.3 km along the same fault planes on which the four most recent quakes struck, the USGS's statement said.

ABC News' KJ Edelman contributed to this story.