The tsunami alert was called off Wednesday in Indonesia after a powerful shallow 7.9 earthquake was reported of the island of Sumatra as information of an undetermined number of casualties emerged, Reuters reported.
Neighbouring Australia had also issued a tsunami watch for parts of its western coast and then cancelled it.
“There are some who have died,” said Heronimus Guru, the deputy head of operations with the National Search and Rescue Agency. He did not know how many, but any rescue operation will be hampered by the dark, which falls early in the tropical archipelago.
There were no immediate reports of damage, but the shallower a quake, the more dangerous it is. The U.S. Geological Survey originally put the magnitude at 8.2, and then 8.1, before lowering it to 7.9.
The epicenter of the quake was located 502 miles southwest of Padang, the U.S. Geological Survey said. It was six miles deep.
Heronimus Guru, the agency's deputy head of operations, told Reuters the earthquake had killed some people, but that he did not know how many.
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"So far there have been no reports (of damage) yet," Andi Eka Sakya, an official of the National Meteorological Agency, told TVOne. "In Bengkulu (on southwest coast of Sumatra) they didn't feel it at all."
President Joko Widodo was staying overnight at a hotel in Medan in North Sumatra and was safe, palace officials said. A Medan resident said he didn't feel the quake.
Indonesia, especially Aceh, was badly hit by the Indian Ocean tsunami in 2004.
A 9.15-magnitude quake opened a fault line deep beneath the ocean on Dec. 26, 2004, triggering a wave as high as 17.4 meters (57 feet) that crashed ashore in more than a dozen countries to wipe some communities off the map in seconds.
The disaster killed 126,741 people in Aceh alone.
Indonesia straddles the so-called "Pacific Ring of Fire," a highly seismically active zone, where different plates on the earth's crust meet and create a large number of earthquakes and volcanoes.