Residents of Dili ran screaming from buildings when the shaking began. Local reports say some people started banging on bamboo drums and on metal objects to sound the alarm.
The U.S. Geological Survey placed the epicenter about 90 miles (145 km) east of Dili at a depth of about 22 miles (35 km). The shaking lasted for more than 30 seconds at 7:15 p.m. local time.
The former Portuguese colony of East Timor has had a troubled history before and after it gained independence from Indonesia in 2002.
President Ramos-Horta was critically injured in an assassination attempt last February in a failed coup, apparently perpetrated by a renegade soldier who died in the attack.
The country comprises roughly the eastern half of the island of Timor, which it shares with Indonesia, as well as a small enclave in western parts of the island.