A magnitude-7.7 earthquake struck off Indonesia’s eastern Flores region, leaving at least 47 people dead and triggering tsunami warnings as authorities urged residents to move away from coastal areas and riverbanks.

The United States Geological Survey reported Friday that the earthquake occurred offshore near Flores. Its epicenter was located about 42 miles north-northwest of Ende, in Indonesia’s East Nusa Tenggara province.

Indonesia’s National Disaster Management Agency reported Saturday that the death toll had reached at least 47.

Emergency crews were still unable to reach Nagekeo, the area nearest the earthquake’s epicenter, because landslides had blocked roads and communications had been disrupted, according to officials.

“The quake was massive, the shock was so strong,” Nona, a 51-year-old resident of Talibura, a village in East Nusa Tenggara, told Reuters. “There were 13 of us inside the house and we all ran to save ourselves.”

In the port city of Maumere, rescuers earlier reported finding 20 people dead, six injured and two others trapped beneath debris, according to Fathur Rahman, the head of the local rescue agency. Maumere serves as the principal town of Sikka Regency on Flores Island.

People remained trapped inside several structures in areas hit by the earthquake, while landslides were reported to have cut off multiple roads and complicated rescue operations.

Initial assessments indicated that 157 homes suffered severe damage, while another 41 sustained moderate damage and 148 had minor damage. Officials also reported damage to 87 schools, 18 health facilities, five religious sites and six government or office buildings, in addition to other infrastructure.

Strong shaking was felt across large portions of Flores Island, where significant damage was reported in several locations.

Yohanna Embu, who lives in Sikka Regency, said the earthquake damaged numerous buildings and sent frightened residents scrambling toward higher ground.

“Many buildings here were damaged. … I saw that the waiting room at the port terminal in Maumere had collapsed,” she said.

Indonesian officials initially issued tsunami warnings covering portions of East Nusa Tenggara, West Nusa Tenggara, South Sulawesi and Southeast Sulawesi. Authorities advised people to avoid beaches and riverbanks, while residents along the coast were told to seek higher ground. The earthquake occurred beneath the sea near Flores Island at a relatively shallow depth.

The main earthquake was followed by two aftershocks.

At St. Peter Major Seminary in Sikka, students attending morning Mass fled after the roof of an assembly hall collapsed, according to the seminary’s rector, the Rev. Guidelbertus Tanga. The school, known locally as Ritapiret Seminary, is located on the predominantly Catholic island of Flores.

“Our students and nuns ran out in panic beneath a collapsing roof,” Tanga said, “At least one priest suffered a broken leg after jumping from the second floor of a building during the quake.”

Australia’s tsunami warning center separately determined that the undersea earthquake posed “no tsunami threat to the Australian mainland, islands or territories.”

Indonesia is an archipelago made up of more than 17,000 islands and frequently experiences earthquakes and volcanic eruptions. The country lies along the Pacific Basin’s “Ring of Fire,” a region characterized by numerous active volcanoes and major fault lines.

Flores has experienced deadly earthquakes and tsunamis before. In December 1992, a magnitude-7 earthquake generated a tsunami that killed roughly 2,500 people on Flores, in the eastern part of the Indonesian archipelago.

The latest disaster follows a magnitude-7.4 earthquake that struck western Colombia on Monday, causing extensive damage.

Earlier in June, two powerful earthquakes measuring 7.2 and 7.5 struck in succession in Venezuela. More than 6,000 people were killed, according to government figures.