The earthquake hit Indonesia at 4.47pm GMT, rocking the major island of Java.
Buildings were badly damaged across the region although no reports of injuries or deaths have been confirmed.
Shocking photos show walls cracked, windows shattered and some smaller buildings collapsed.
It struck just 63 miles from the city of Bandung, which is home to more than two million people and popular with tourists
Testimonies left on earthquake tracker CSEM EMSC recorded panic among those living in the region.
One person said: “We felt the house shaking.”
Another said: “I thought someone was trying to break into our apartment. I ran from room to room trying to find out what was going on. Freaky.”
A third said: “Doors and windows rattle. And lights out shortly after.”
The quake struck at a depth of 60 miles.
It had initially registered as 6.8 before being downgraded to 6.4 and then upgraded slightly to 6.5.
An estimated 90 million people may have felt the quake, EMSC-CSEM estimated.
Buildings have been damaged across Java following the Indonesia quake today