A strong earthquake hit the western coast of Indonesia's Sumatra island Tuesday, prompting authorities to issue a tsunami alert.
The quake with a preliminary magnitude of 6.4 struck nearly 160 kilometers (100 miles) off the coast of the town of Bengkulu, the Meteorological and Geophysics Agency said.
The U.S. Geological Survey put the quake at a weaker 5.7 magnitude.
A series of powerful earthquakes and dozens of aftershocks in the same region killed 23 people and damaged or destroyed thousands of buildings last month.
There were no immediate reports of injuries or damage from Tuesday's trembler, which registered at a depth of 20 kilometers (12.5 miles).
Tsunami alerts are routinely issued in Indonesia, where a monstrous quake in 2005 spawned the Asian tsunami that killed more the 230,000 people in 11 countries, but a temblor of Tuesday's size rarely causes giant, destructive waves.
Indonesia, the world's largest archipelago, with a population of 235 million people, is prone to seismic upheaval due to its location on the "Ring of Fire," an arc of volcanos and fault lines encircling the Pacific Basin.