The Pacific Tsunami Warning Centre in Hawaii said a tsunami watch was in effect for Indonesia, India, Sri Lanka, Australia, Myanmar, Thailand, the Maldives and other Indian Ocean islands, Malaysia, Pakistan, Somalia, Oman, Iran, Bangladesh, Kenya, South Africa and Singapore.
Residents across Sumatra fled their homes in panic, local media reported.
Residents in Banda Aceh reported the ground shaking violently."
People are in a panic, and there are traffic jams everywhere in Banda Aceh," local Metro TV reported.
Said, an official at Indonesia's Meteorology and Geophysics Agency who goes by only one name, said a tsunami warning was issued for cities all along the coast of Sumatra island.
There was chaos in the streets, with shaking continuing for nearly four minutes.
"I was in the shower on the fifth floor of my hotel," Timbang Pangaribuan told El Shinta radio from the city of Medan. "We all ran out. ... We're all standing outside now."
He said one guest was injured when he jumped from the window of his room.