PADANG, Indonesia —

The death toll from flash floods and landslides on Indonesia’s Sumatra island rose to 164 on Friday, with 79 people missing, authorities said, as rescue workers found their efforts hampered by damaged bridges and roads and a lack of heavy equipment.

Monsoon rains caused rivers to burst their banks in North Sumatra province Tuesday. The deluge tore through mountainside villages, swept away people, and submerged more than 3,200 houses and buildings, the National Disaster Management Agency said. About 3,000 displaced families fled to government shelters.

The death toll in North Sumatra province rose to 116, while 25 people died in Aceh. Rescuers also retrieved 23 bodies in West Sumatra, National Disaster Mitigation Agency’s Chief Suharyanto said.

“Mudslides that covere

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