JAKARTA, Indonesia - The death toll from an Indonesian tsunami has risen past 280 with more than 1,000 people injured. The tsunami struck Sunda Strait coastal areas along western Java and southern Sumatra islands without warning in the darkness Saturday night.

A disaster agency spokesperson, Sutopo Purwo Nugroho, said 281 people were killed and 1,016 others injured. Fifty-seven people were missing but that number was expected to rise.

The waves that swept terrified people into the sea followed an eruption and possible landslide on Anak Krakatau, one of the world's most infamous volcanic islands.

Dramatic video posted on social media showed an Indonesian pop band named "Seventeen" performing under a tent on a popular beach at a concert for employees of a state-owned electricity company. Dozens of people sat listening at tables covered in white cloths while others bobbed to the music near the stage as bright strobe lights flashed and theatrical smoke was released. The video ended seconds after the tsunami's waves hit.

The worst-affected area was the Pandeglang region of Java's Banten province, which encompasses Ujung Kulon National Park and popular beaches, the agency said.

Indonesian President Joko "Jokowi" Widodo expressed his sympathy and ordered government agencies to respond quickly to the disaster. "My deep condolences to the victims in Banten and Lumpung provinces," he said. "Hopefully, those who are left have patience."

It was the second deadly tsunami to hit Indonesia this year. In September, a tsunami killed more than 2,500 people on the island of Sulawesi. That tsunami was accompanied by a powerful earthquake that gave residents a brief warning before the waves struck.

Associated Press contributed to this report.