JAKARTA, Sept. 30 (Xinhua) -- The death toll from multiple strong earthquakes and an ensuing tsunami which devastated Indonesia's Central Sulawesi province has jumped to 832, a spokesman of the national disaster management agency said on Sunday.

Some 540 people were seriously injured and 16,732 people were forced to flee their homes, spokesman Sutopo Purwo Nugroho said.

The death toll was expected to rise as assessment of the risks and evacuation were underway, according to the spokesman.

Most of the casualties were reported in Palu, the provincial capital, and the adjoining Donggala district, with 821 and 11 deaths respectively, Sutopo said.

Two other districts which were also stricken by the quakes and tsunami have not reported casualties as communications were cut off, he added.

Many were believed still buried under the rubble as search and rescue operations were underway.

A wide area was affected by the natural disaster, and lack of personnel and heavy machinery equipment hindered relief operations, he added.

Meanwhile, Indonesian President Joko Widodo arrived in Palu Sunday and urged for rescue efforts, according to media reports.

Multiple powerful and shallow quakes of 6.0, 7.4 and 6.1 magnitude followed by a tsunami devastated the central province on Friday.

Spokesman of the Information and Communication Ministry Ferdinandus Setu said on Saturday that Palu's airport has been operating but only serving relief flights.

Communication facilities have also been functioned in several parts of the quake-ravaged province.

Photos released earlier by the Indonesian air force and the disaster management agency showed collapsed buildings and bridges, and the injured lying in a yard in front of a hospital and waiting for treatment.

Sutopo said earlier that survivors and the injured people were in need of aids including fast food, baby food, medicines, tents and blankets. More rescuers and heavy machinery equipment were also needed.

Indonesia is prone to earthquakes as it lies on a vulnerable quake-affected zone called the Pacific Ring of Fire.

The country's Lombok Island was hit by multiple quakes hovering from 6.4 to 7.0 magnitude from late July to August this year, leaving at least 560 people dead.