At least 38 people have been killed after a 7.7-magnitude 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. BBC reported.

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.

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."