The quake was initially registered at 6.3 in magnitude, but the U.S. Geological Survey — which measures temblors across the world — later revised the magnitude to 6.1.

“Till now, the reports that I have received say five to six lives have been lost,” Bhutan’s Home Minister Minjur Dorji said.

The quake sent boulders down the hillsides in eastern Bhutan, blocking roads to remote, hilly regions, he added. The strong quake damaged monasteries, homes and dzongs — Bhutanese forts — and reportedly destroyed at least one home.

Two monks were trapped inside a collapsed monastery in Bhutan’s eastern Tashigang district, Dorji said.