The death toll in the devastating earthquake and tsunami that hit Indonesia’s island of Sulawesi increased to 832 on Sunday as rescue workers combed through concrete and lumber searching for survivors, the country’s disaster management agency said.

The toll was confirmed by agency spokesman Sutopo Purwo Nugroho who has estimated that 2.4 million people were impacted by Friday’s 7.5-magnitude earthquake, CNN reported.

Survivors walked through floodwater and piles of debris on Sunday.

A shopping mall turned into rubble and the large dome of a mosque collapsed in the coastal city of Palu, home of 350,000 people.

Hundreds were badly injured and at least 17,000 people were left homeless, Nugroho said.

The lack of heavy equipment and personnel has slowed down rescue efforts in Palu, where workers were scrambling to rescue about 50 people trapped beneath the debris of a collapsed hotel.

As Indonesia’s President Joko Widodo heads to visit Palu on Sunday, the scale of the earthquake’s destruction is still unclear.

Electricity and communications have been cut off and roads that are severely damaged or blocked by landslides are making it difficult to assess the damage, Nugroho said.

Jan Gelfand, head of the International Red Cross in Indonesia, has said that help was also on the way for the fishing towns of Donggala and Mamuju, two areas feared to be heavily devastated.

“The Indonesian Red Cross is racing to help survivors but we don’t know what they’ll find there,” Gelfand told CNN, adding “This is already a tragedy, but it could get much worse”.

The horrific scene began on Friday afternoon when a series of tremors rocked Sulawesi and a 7.5 magnitude earthquake triggered a tsunami that sent waves of “about 10 feet high” to the beaches of Palu and Donggala.

An early tsunami warning had been issued by the Indonesian meteorological agency, but was later lifted after the agency ascertained that the water had receded.

The quake and tsunami comes a month after a three temblors hit several islands in the South Pacific and Indonesia, including Lombok, which is still recovering from the effects of an August 5 earthquake that killed more than 430 people.