Several bridges collapsed, trees fell and blocked some roads in Indonesia and at least one ship sank in high waves triggered by the cyclone, complicating search and rescue operations, BNPB said.
Agustinus Payong Boli, deputy head of the East Flores government, said rescuers halted evacuations because a storm was still raging and they needed heavy equipment.
In Lembata, where at least 20 people died, authorities feared bodies had been washed away.
“We are using rubber boats to find bodies at sea. In several villages, flash floods hit while people were sleeping,” Thomas Ola Langoday, deputy head of Lembata district government, told Reuters by phone.
President Joko Widodo offered his condolences and urged residents to follow the direction from field officers during extreme weather.
“I have ordered for disaster relief efforts to be conducted quickly and well,” he said in remarks streamed online.
The Seroja cyclone hit the Savu sea southwest of Timor island in the early hours of Monday, Indonesia’s weather agency said.