A strong earthquake measuring 6.3 on the Richter scale jolted Bhutan Monday afternoon, Xinhua quoted the China Earthquake Networks Center as saying. The tremor, with the epicenter at 27.3 degrees north latitude and 91.5 degrees east longitude, struck at 4:53 p.m.(Beijing Time), the center said. Residents in Lhasa, capital of southwest China's Tibet Autonomous Region that neighbors Bhutan, felt the tremor obviously. But no casualties or property losses were immediately reported in the Chinese territory, a spokesman with the Tibet Regional Seismological Bureau said.