JAKARTA, Indonesia — A tsunami apparently caused by the eruption of an island volcano killed at least 222 people around Indonesia's Sunda Strait during a busy holiday weekend, sending water crashing ashore and sweeping away hotels, hundreds of houses and people attending a beach concert.

More than 840 people were reported injured after the tsunami hit late on Saturday, the Disaster Management Agency said. At least 28 others were missing, but the toll could continue to rise because some areas had not yet been reached.

Officials have so far said there were no foreign nationals among the casualties. More than 550 houses and 350 boats were also damaged.

Scientists, including those from Indonesia's Meteorology and Geophysics agency, said the tsunami could have been caused by undersea landslides or those occurring above sea level on the volcano's steep outside slope following the eruption of Anak Krakatau.

It translates to "Child of Krakatoa," a volcanic island formed over years after one of the largest eruptions in recorded history occurred at the Krakatoa volcano more than a century ago. The scientists also cited tidal waves caused by the full moon.

Residents inspect a house damaged by a tsunami in Carita, Indonesia, Sunday, Dec. 23, 2018. AP

Dramatic footage 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 the state-owned electricity company.

As bright strobe lights flashed on stage, a child could be seen wandering through the crowd. Then, as the second song was about to begin with the drummer pounding, the stage suddenly heaved forward, throwing the band and all their equipment into the audience.

The band released a statement saying their bass player and road manager were found dead, while three other band members and the wife of one of the performers remained missing.

"The tide rose to the surface and dragged all the people on site," it said. "Unfortunately, when the current receded our members are unable to save themselves while some did not find a place to hold on."

Tourists were also affected during the long holiday weekend ahead of Christmas.

"I had to run, as the wave passed the beach and landed 15-20m (meters) inland," Norwegian Øystein Lund Andersen wrote on Facebook. The self-described photographer and volcano-enthusiast said he was taking pictures of the volcano when he suddenly saw a big wave come toward him.

"Next wave entered the hotel area where I was staying and downed cars on the road behind it. Managed to evacuate with my family to higher ground trough forest paths and villages, where we are taken care of (by) the locals. Were unharmed, thankfully."

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

The Anak Krakatau volcano lies in the Sunda Strait between Java and Sumatra islands, linking the Indian Ocean and Java Sea. It erupted about 24 minutes before the tsunami, the geophysics agency said.

The 1,000-foot-high volcano, about 124 miles southwest of capital Jakarta, has been erupting since June. In July, authorities widened its no-go areas to 1.24 miles from the crater.

Gegar Prasetya, co-founder of the Tsunami Research Center Indonesia, said the waves were likely caused by a flank collapse — when a big section of a volcano's slope gives way. He said it's possible for an eruption to trigger a landslide above ground or beneath the ocean, both capable of producing a tsunami.

Residents inspect the damage to their homes on Carita beach on December 23, 2018, after the area was hit by a tsunami that may have been caused by the Anak Krakatoa volcano. SEMI / AFP - Getty Images

"Actually, the tsunami was not really big, only one meter," said Prasetya, who has closely studied Krakatau. "The problem is people always tend to build everything close to the shoreline."

In September, more than 2,500 people were killed by a quake and tsunami that hit the city of Palu on the island of Sulawesi, which is just east of Borneo.

Saturday's tsunami triggered memories for some of the massive 9.1-magnitude earthquake that hit on Dec. 26, 2004. It spawned a giant tsunami off Sumatra island in western Indonesia, killing more than 230,000 people in a dozen countries — the majority in Indonesia. The vast archipelago of more than 17,000 islands is home to 260 million people.

Roads and infrastructure are poor in many areas, making access difficult in the best of conditions.