A search and rescue operation is under way to find survivors in Flores, an island in eastern Indonesia.
At least 38 people have been killed after a magnitude 7.7 earthquake struck Indonesia early on Saturday, the nation's disaster mitigation agency has said.
The official death toll has been rising as a search and rescue operation gets under way. The BNPB agency said several people had been injured to varying degrees.
Buildings in the region have been damaged by the quake and the dozens of aftershocks that followed.
The quake struck the island of Flores shortly before 05:00 local time on Saturday (22:00 GMT on Friday). It had a depth of 15km, Indonesia's meteorology and geophysics agency stated.
The shallower an earthquake is, the more destructive its effects on the surface tend to be.
Strong aftershocks were felt in the same area, including one with a magnitude of 6.1.
Later on Saturday, a magnitude 6.4 earthquake was felt in North Sumatra at a depth of 163km.
Video taken at the port in Maumere showed large chunks of concrete breaking off the terminal building onto passengers waiting to board an inter-island ferry. Some were thrown into the sea when the gangway to a ship collapsed.
Emanuel Melkiades Laka Lena, governor of East Nusa Tenggara province, told a news conference that they were killed in their sleep by collapsing rubble.
Arnold Welianto, who lives in Talibura, a village near the coastline in Sikka, East Nusa Tenggara, said he was awoken by the "very strong shaking", adding: "I was startled awake and immediately went to my child's room."
He told the BBC that many people had already fled into the hills.
"Some other residents were standing along the roadside because the sea had also receded," he explained. "The water remained low for quite some time, so everyone panicked and ran - I went around to the community health centre, and the people there had already been evacuated."
A tsunami warning was issued but lifted around three hours after the initial jolt when no significant sea level rise was detected.
A stream of people could be seen moving inland on motorbikes after authorities issued a tsunami warning. BNPB said 2,000 people had evacuated or relocated on their own.
It said three fatalities had been recorded in Sikka province, six in Manggarai province, and five in East Manggarai province.
At least two others had been seriously injured and 11 slightly injured, the disaster agency added.
Welianto said many residents of Talibura were choosing to remain outdoors as the aftershocks meant they were afraid to return to their homes.
Yulian Juita Ekalia, a university lecturer from Ruteng, a city to the west of the epicentre, said she had dragged her stove outside and was cooking there for fear of further tremors.
"I have never felt an earthquake this big," she told news agency AFP. "It felt like we were on a trampoline - it was really scary."
It will take time to assess the full extent of the destruction in the region, which is remote and mountainous.
Preliminary reports indicated 54 houses had been severely damaged, as well as five healthcare facilities, three places of worship, six government buildings, an educational institution and a warehouse.
Manggarai province is among the most affected areas, BNPB said.
It advised people to remain calm, and to stay away from coastal areas and structures showing signs of damage.
Indonesia is prone to earthquakes and volcanic activity, lying along the meeting point of three major tectonic plates.